ok well, if you want to save money, then forget the headset, tie, shirt epaulettes and the confuser for the time being. You won't need the confuser until you actually start taking your exams and the headset you won't really need until you've qualified and prefer to use your own.
The PPL study package will save you a fair amount of money to begin with as I think it's something like £50 or maybe more to buy the bits seperately.. .The only things you'll need on your early lessons will be map, kneeboard, pen, spare pen, sunglasses, checklist & a watch. I might have missed something out on that little bit, if I have, I'm sure someone will give me a nudge and let me know.. .Personally I would, before any of that, have a trial lesson with a local flying school to see if you actually enjoy it and feel it's for you.
With regards for your medical which you've asked about, if after your trial lesson you do really want to persue this and are wanting to take it to CPL or ATPL level, then go for a Class 1 so you know whether or not you will be able to follow it through to the end.
I've never read the Pratt books so I'm unable to comment on them, although I do find the Trev Thom books quite easy to understand.
Also forgot about learning in a twin for starters, try the basics first a nice C152 are fun to learn in, and cheapish on the hourly rate.