While the inquiry provided us with some gripping stuff last week and yesterday, today's session has been less revelatory.

That said, there's plenty more to come this week.

Join us tomorrow morning from 09:45 when Ofgem official Dr Edmund Ward will return to face more questions.

Now, we're off to escape into that evening sunshine...

BBC News NI

A manager of the RHI scheme told the inquiry that he was never told about articles in two national newspapers warning about abuse of the similar initiative that was running in Great Britain.

Image source, Pacemaker

Stuart Wightman said if he had been aware he's sure the content would have been escalated to the minister.

The articles appeared in the Daily Mirror and Guardian in late 2014 and early 2015.

Returning to the issue of the approval for the RHI scheme that had lapsed in spring 2015, inquiry chair Sir Patrick Coghlin still can't quite get his head around it.

Stormont's finance department has said it wasn't responsible for checking that its approval for the scheme had run out.

Instead it was up to DETI's energy officials to know that and to then apply for reapproval for the RHI scheme.

Image source, RHI Inquiry

Sir Patrick wants to know why DETI's own finance officials - rather than the energy team - couldn't just keep a record of all of the approvals received for projects across the department.

"That may or may not be sensible," he says.

In a withering aside, he adds: "But I suppose sensible may not be the right word for this sort of organisation."

Mr Wightman prepared a briefing paper for DETI colleagues who were meeting Department of Finance and Personnel officials in June 2015.

Mr Aiken picks out some salient points from the six-page briefing - one of which is a claim that the RHI scheme "still represents value for money".

Mr Wightman accepts that he wrote this because he didn't realise at the time that claimants were being overcompensated.

There's another inaccuracy resulting from his misunderstanding of the requirement for a review of the scheme - he asserted in the briefing that in 2014 a decision was taken to wait before considering tariff changes due to low oil prices.

When asked by Mr Aiken, Mr Wightman accepts that this was not the case.

Mr Wightman says DETI had approached Mr Ellis in the hope that he would provide a "piece of independent work" about how the RHI scheme was being used by poultry farmers.

He says the department didn't have time to commission a report from external consultants.

Image source, Getty Images

Inquiry panellist Dame Una O'Brien says the sources for the research should've been cited.

Her colleague Dr MacLean says there's "always a dilemma" because the "best information you're going to get is from those with the greatest involvement and therefore the greatest vested interest".

"The better your numbers the more suspicious you've got to be of the source than you've got them from."

In preparing his paper for DETI in July 2015, Mr Ellis met a major poultry farmer for Moy Park.

Tom Forgrave (below) was the chairman of the Ulster Farmers' Union's poultry committee and a claimant on the RHI scheme.

Mr Forgrave shared data from his farm, which the agriculture official incorporated into his research paper on the poultry sector's use of the RHI scheme.

When the report was submitted, DETI officials met UFU members, including Mr Forgrave, to discuss it and little did the civil servants know that it had already been shared with him by Mr Ellis.

Asked about when he found out that a scheme claimant and UFU member had input in the document, Mr Wightman says he first became aware of it during Mr Ellis's appearance at the inquiry in April this year.

He says it left him "bemused, very frustrated" and he felt he had been "taken for a bit of ride".

In July 2015, DETI officials running the RHI scheme asked Cathal Ellis, an official in Stormont's agriculture department, to give them a better understanding of how the poultry sector was using the initiative.

In an email to Mr Ellis, Mr Hughes said the had been "led to believe" that RHI scheme heating systems in "some [poultry] houses are running 24/7".

Image source, Getty Images

Responding, Mr Ellis said he was aware of such rumours but said it didn't apply to farms in Northern Ireland.

He said he would discuss the issue with installers of biomass boilers to get a sense of the heating requirement for poultry farms and would draw up a report for DETI.

Mr Aiken says the original 2012 finance department approval letter for the RHI scheme "reappears" in June 2015, while the 2014 approval letter for the domestic scheme was also exhumed.

The following day, DETI's top management team was informed that approval for the scheme had expired.

Image source, RHI Inquiry

Mr Aiken quotes from an email between two officials that includes the term "irregular expenditure".

"It seems now that frantic work is underway to take account of the fact that... approval isn't in place," he says.

In June 2015, Mr Wightman was still seeking clarity on the budget that would be available for the RHI scheme.

He'd been asking finance officials about the issue for weeks and it had become an increasingly pressing issue because the spend on the scheme had been rising sharply.

Image source, Getty Images

Among his questions were whether unspent from the scheme's budget in previous years could be used in the 2015-16 year - about £14m that was set aside for the first four years of the initiative hadn't been used.

He also asked whether surplus money from the Northern Ireland's overall budget could be dipped into for the RHI scheme.

Mr Wightman noted in a document at the time that due to the growing number of applications to the scheme meant that monthly spending on it had risen from £430,000 to £1.3m.

When Stormont's Department of Finance and Personnel granted approval to the RHI scheme it stipulated that there should be a review of the initiative by April 2015.

DETI overlooked that requirement and at that point financial approval for the scheme expired, meaning that money was being spent on it without authorisation.

Asked if he ever noticed that the review hadn't been carried out, Mr Wightman says he got mixed up and thought the need for a review referred to a later stage of the scheme

"My first reaction was that my predecessors did a review of the scheme," he says, adding: "At this stage I probably hadn't seen a copy of the approval letter."

Mr Aiken moves into the development of proposals to introduce cost controls to the RHI scheme.

DETI civil servant Mr Hughes started work on a policy document that covered cost controls on 29 May 2015.

A version of that document was attached to the important submission sent to new DETI minister Jonathan Bell on 8 July that year

Image source, Getty Images

There were 15 versions of the document - the final one was from the end of August - and the 29 May version proposed that the changes to the scheme should take place in October 2015.

It still contains references to proposed reductions to the scheme subsidies in April 2017 and 2018.

There is, Mr Aiken notes, no mention of degression, a budget protection measure that was used in the GB RHI scheme.

It allowed the tariff to be lowered in response to increased demand, keeping the initiative's budget on course.

Image source, Getty Images

Sir Patrick calls time on the morning session and we're off to grab a sandwich and maybe catch some sunshine.

See you at 14:00.

Mr Aiken puts it to the witness that in May 2015 he still didn't know that claimants from the RHI scheme were getting more money than they should.

He says Mr Wightman thought there were more people on the scheme than had been envisaged, quicker than expected "and it's a matter of how do we square the circle of having enough money to pay them".

Image source, RHI Inquiry

Mr Wightman says that's right and that he thought "this is great" because Northern Ireland could therefore do more than its fair share to achieve the EU directive's renewable heat target.

"You thought you had a budget problem, not an overcompensation problem," says Mr Aiken.

Image source, Getty Images

DETI's then permanent secretary Dr Andrew McCormick was due to meet officials from Whitehall's Department for Energy and Climate Change (DECC) to discuss the RHI scheme.

Mr Wightman prepared a briefing about the scheme for Dr McCormick in May 2015 and in it he said the scheme had "taken off massively".

But he said that "success comes at a price" and explained that the spending on the scheme was rising by about £100,000 a month.

Inquiry panel member Dr Keith MacLean (below) notes that Mr Wightman was still suggesting that DETI should apply for more money for the RHI scheme in May 2015 when finance officials were insisting that spending on the initiative should be stopped.

Asked if there was ever a discussion about that, Mr Wightman says he would have spoken with Mr Hughes, who was working hands-on with the scheme.

Image source, RHI Inquiry

"I was particularly frustrated and obviously [in] panic mode - we can't stop this scheme, we have to honour commitments, we need new legislation to stop it," he says.

The witness adds that that led to the series of meetings with the senior management team in June.

In May 2015, it started to become obvious to DETI that the RHI scheme had increased to the extent that a bigger budget would be needed.

A DETI finance official told Mr Wightman was told to "please stop entering into commitments immediately to ensure that monthly cumulative expenditure does not increase".

Image source, Getty Images

Mr Wightman says it "very quickly escalated" and there were meetings with senior managers but the inquiry barrister Mr Aiken observes that there's no written record of what happened during those "even though [DETI was] now in crisis mode".

Mr Aiken asks if not taking notes had simply became "the new normal" and he wonders whether some sort of written record should've been made in the case of an "unhappiness summit" about the scheme.

The witness says he can't remember the policy but there would often have been a follow-up email that detailed some of the action points that came from the meetings.

In an email to Fergal Hegarty of the renewable energy firm Alternative Heat in July 2015, DETI official Seamus Hughes appears to offer some incorrect information about plans for tiering in the RHI scheme.

Mr Aiken says either Mr Hughes has misunderstood the issue or he was misleading Mr Hegarty.

Image source, Getty Images

Mr Wightman says "the period at the end of June/July was pretty manic" and he thinks it was a genuine misunderstanding on Mr Hughes' part: "At that point in time we were firefighting."

Mr Aiken says that "matters were clearly chaotic" and he wonders if any thought was given to drafting in additional staff.

Mr Wightman says he can't recall any such suggestion: "I found it a very frustrating period."

In mid-May 2015, DETI decided to go ahead with tiering trigger of 1,314 hours of heating system operation.

Mr Aiken says there's no sign of any explanation of the rationale for the decision and it seems it may have been taken "without knowing why".

Image source, Getty Images

Asked why it was deemed to be an "appropriate thing" to do, Mr Wightman says he did some of his own investigation work to get a better understanding of tiering as a cost control.

He says he knew it was a "really important part" of how the similar RHI scheme worked in Great Britain.

Mr Aiken says some new evidence has emerged about cost controls and the particular matter of tiered tariffs for the RHI scheme.

Tiering is one way way of controlling the cost of the scheme and works by dropping the tariff on offer once a certain limit of usage has been reached, with the intention of preventing a claimant from overusing their heating system to collect more cash.

In February 2015, DETI official Seamus Hughes sent documentation to scheme administrator Ofgem with proposals for a 7p per kW tariff for heating systems of 200kW and above to stimulate growth.

The next month, he sent another document including proposals for a cost control - it would see the biomass tariff reduce in April 2017 and again in 2018 by 33% but Ofgem wasn't keen.

Ofgem's reaction was to say that it "could open another opportunity for fraud or gaming the scheme".

The administrator suggested that one way to manage that was to pay a higher rate only for the first 1,314 hours of a heating system's operation but Mr Wightman says he doesn't remember this proposal.

The DUP adviser Mr Brimstone (below) called Mr Wightman to discuss the RHI scheme, possibly in 2015.

The witness says Mr Brimstone didn't identify himself as a ministerial adviser and he says he felt the call was "kind of unusual" because of how it started.

He says that Mr Brimstone opened by saying: "I believe you're the man to talk to about RHI."

That led Mr Wightman to treat the call as one from a potential applicant to the scheme - a type he received commonly - and he talked Mr Brimstone through the process.

Mr Wightman says he would "have been on my guard a bit more" if he'd known that Mr Brimstone was a DUP adviser when they were speaking about the RHI scheme.

But he adds that afterwards he knew he'd heard Mr Brimstone's name from somewhere and later realised who he was, given that Mr Brimstone had become a prominent figure due to the Red Sky scandal over Housing Executive contracts in 2013.

Mr Brimstone has confirmed that he's a claimant on the RHI scheme and his brother Aaron is also a beneficiary, the Irish News has reported, external.