Near London
Hi Zonkor,
OK, let's talk about London.
London is a very big place and travel within London is very expensive and time consuming. So you need to choose either, somewhere to fly that is close to where you will be staying, or somewhere to stay that is near to where you will be flying. You don't want to be travelling for much more than about an hour in either direction to and from the airfield.
There are probably good places to do instrument flying in a ring of flying establishments that extends all around London. In the West there are places at White Waltham and Booker , Denham and probably Elstree . In the North there is Stapleford and North Weald aerodromes. In the South there should be good places at Biggin Hill and Redhill. I don't know the good places on the Eastern border of London, but I'm sure there will be people here who will.
Be careful of some of the advice you get here. You ask for places near London or Birmingham and someone suggests Humberside!
Regards,
BP.