GPs
I believe the Doctors at the top of the list have been there longer and new doctors get added at the bottom.
The longer you have been registered with a surgery the more likely you are to be with a doctor near the top of the list.
I say that because when I registered with Dr Robertson at Marcham Road, and my wife and children registered with Dr Crossley at the Abingdon Surgery, they were near the middle / bottom, and now they are both at the top.
(Long Furlong Medical Centre:
Dr A L Keeling
Dr T E Knowell
Dr E Allan
Dr J Moore
Dr N Elwig)