Sciver & Davidson-Richards hit centuries as England recover brilliantly to close on 328-6, leading by 44
Sciver ends on 119*, Test debutant Davidson-Richards caught for 107 off final ball of day
Hosts were 121-5 after lunch in reply to South Africa's 284
Jones bowled by spinner Mlaba for a duck, Captain Knight (8) run out
Bosch also traps Beaumont (28) lbw & bowls Lamb (38) after England openers put on 65
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Alex Hartley
Former England bowler on BBC Test Match Special
It was wide outside the off stump. The keeper has dived across and put off Sune Luus and it's hit her right where I can't say.
They would have wanted to get Knight just before lunch especially after a poor shot and it would have carried them positively into lunch. Poor cricket on both sides really.
SA 86-2
Oh dear. Ohhhh dear.
Do not give Heather Knight a lifeline.
Marizanne Kapp draws a thick outside edge that is heading straight into Sune Luus' hands but the keeper dives unnecessarily in front of her, a complete distraction, and Luus is unable to hold on.
She literally did not have had to move for it. That is a steely glare from Kapp. I would not want to be on the receiving end of that.
Alex Hartley
Former England bowler on BBC Test Match Special
I was wondering who the third person was. I was looking around to see who you were talking about!
Melissa Story
BBC Test Match Special
Katherine Brunt has arrived. So we now have three of the greatest England bowlers in the commentary box...Anya Shrubsole, Katherine Brunt and...Alex Hartley.
Nadine de Klerk gets one to nip back in viciously at Nat Sciver and strike her high on the leg, taking her by surprise. Consecutive maidens.
Can South Africa sneak another wicket before lunch? They'd be delighted to have taken three on a flat pitch like this.
Alex Hartley
Former England bowler on BBC Test Match Special
You can't blame South Africa. they haven't played a Test match since 2014 so they've not really had a chance to get that cohesion and form those bowling partnerships. They've only had one warm up game to try and get that sorted. It's not easy to just bring it about that quickly.
Knight pokes uncertainly at a good length delivery from Marizanne Kapp and she is very lucky not to get an edge on it. A rare loose shot from the England skipper.
Another maiden from Kapp.
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Stephan Shemilt
BBC Sport chief cricket writer at Taunton
I'm trying to think of the last time I saw a wicket keeper wearing glasses...
Here's the first of those two wickets that fell to Anneke Bosh, getting Tammy Beaumont trapped lbw.
Consecutive boundaries for Nat Sciver as she gets off the mark with a crunching pull shot through mid-wicket before slicing a less convincing cut over the slips for four more.
That's a shame for South Africa. After that second wicket they had a real opportunity to build some pressure before lunch but that's allowed Sciver to get some early confidence.
Alex Hartley
Former England bowler on BBC Test Match Special
It's a good time to have Kapp into the attack with Knight on four and Sciver yet to get off the mark. It's a great time to bring your strike bowler on and get rid of one of these and bring Dunkley or Alice Davidson-Richards to the crease.
The field may not be more attacking but this bowling change certainly is.
She brings back Marizanne Kapp, her strike bowler. She starts with a maiden.
Emily Windsor
Southern Vipers batter on BBC Test Match Special
You'd like to see Sune Luus go a bit more attacking with her field. Nat Sciver is going to be more vulnerable in her first few overs but Luus doesn't seem to be changing anything.
Nat Sciver joins Heather Knight in the middle and South Africa have a chance to capitalise with two new batters in - albeit very good ones indeed.
It's testament to how well Emma Lamb batted that it feels like a significant breakthrough for the visitors and the celebrations that followed.
Alex Hartley
Former England bowler on BBC Test Match Special
That was a great ball from Bosch. She's just found the right line and length with the cross seam. Lamb has tried to dive instead of defend and she's missed and it's just nipped back on her. It was ever so slightly straighter and the opener has to go.
Lamb b Bosch 38 (Eng 74-2)
Bowled through the gate!
Full and straight from Anneke Bosch does the trick for England as Emma Lamb attempts one drive too many and is cleaned up.
Lamb looks disappointed but that is a fine effort from the debutant. That was the only loose shot she played that I can remember.
#bbccricket
Jack Rule: Easy now Lamby!! Running out the captain in your first Test is not the wisest of ideas!
Oh, dear.
Miscommunication between the batters sees them both stranded in the middle of the pitch, it looks a certain run out but the throw is very poor and a dive saves Heather Knight at the keeper's end.
Crisis avoided for England but that wasn't good cricket.
Image source, Getty ImagesFour more to Emma Lamb as Nadine de Klerk drops short and wide and is punished through the off side.
She's played beautifully.