Hi Tim,
I'll leave others who know your neck of the woods to give advice on schools etc as I fly from Wellesbourne near Coventry. However it would probably help if you mentioned
where on the Norfolk/Cambs border you are located as that's quite a large area!
The usual advice is:
1. visit several schools to sample the atmosphere and go for the one where you feel most comfortable
2. phone ahead or visit on a poor-weather day so people will have time to talk to you - the weekends can be very busy
3. never pay for large blocks of lessons unless you use a credit card to protect your money
Don't forget that you will need to pass a medical before you can fly solo, and it is wise to get that out of the way early on. The instructors will give you chapter and verse on the rest of the course.
The only other thing, given that you are 'amply proportioned' would be to sit in various aircraft with the instructor and the doors closed to see if it is comfortable for you. If you are broad shouldered you may find some of the 2 seaters rather cramped - you need to try them for size.
Finally, welcome to the world of private flying - I hope you will really enjoy yourself 'up there'
