Since most instructors are of a similar size (due to the diet of bacon sarnies and coffee) then you might struggle in many 2 seaters when it comes to keeping the aircraft under the max take off weight. Don't worry about your weight for the medical.
Personally I think the best books are the Jeremy Pratt ones for PPL study, you can get them either from the club you join or from shops such as Transair or Pooleys.
Be careful about buying off Ebay, whilst it is usually OK, the books do change periodically and you might find yourself with something out of date, Air Law is the main one to watch for in that regard.
As for schools, as has been mentioned, go and have a look at all the clubs and schools and see where you feel most comfortable. Ask lots of questions and make sure that they don't do things like chop and change instructors regularily. That really stuffs up your training and will cost you more in the long term.
Be very careful about things like accounts and paying upfront. The general rule is just don't, no matter how much the school offers in discounts. There are too many tales around of schools going bust and taking all the money on account with them.
Good luck with it all and enjoy. It is great fun!