Personally, I'd stick to the midwives.

He's a GP. Is he specialised in childbirth? If not, theres no huge advantage over having him there compared to two experienced and specialised midwives. I doubt he could do more than what your midwives could do.


ETA:
I need to decide within the next ten weeks as, if he is NOT going to attend the birth, he cannot continue to provide care until after the birth (insurance reasons).
If he's a GP why can't he provide shared care at his practice leading up the birth? Sorry if this is naive, but I'm a bit confused lol.