Hi Dst,
Welcome to Pprune!
And well done for now having the resources to be able to start flying.
Your choices of schools are:
ACS (Leading Edge) at Cumbernauld, Glasgow or Perth
Tayside at Glenrothes and Dundee
Edinburgh Flying Club
Border Air Training at Cumbernauld
and, possibly (the wild card!) ourselves at Strathaven.
Things to look at are :
Location: how far to travel (petrol can cost 20p a mile), weather (some people say the East Coast has better weather, but it can also get fogged in with easterly winds) and how busy the airfield is (you cannot do circuits - ie learning take-off and landing - at Edinburgh, I understand, so have to fly to Fife for that.)
Aircraft: which types - some like high wing, some prefer low wing, their condition etc
Instructors: how often are they there. Will you have the same one right though training, or will you get passed from one to another or is "your" instructor only available on odd days.
Fellow students/pilots: you can learn a bit from being with them.
Cost: To exaggerate, three hours with an instructor at £100 per hour is obviously worse value than one £250 an hour with an instructor who can teach you the same skills in 60 minutes. So lesson cost is not everything. And beware of other fees like "club membership", "landing fees" and what insurance is offered if you have an accident.
You mention flying as a hobby. If you do not really want to become a commercial pilot at the moment, it might be worth popping down to see us at Strathaven and having a shot in our C42 "microlight". The C42 is a modern German-built light aircraft that can just squeeze into the microlight category (by 500 grams!).
Quite a few of our folk have got their microlight licence and then spent three hours upgrading to an NPPL for light aircraft. And for the next year and a half, or so, there is a very clear route from microlight to the new European Light Aircraft Pilots Licence and then on to the EASA SEP.
ps. Don't worry about "open days". Most flying schools should be happy to see you and have a chat most days - after all, you are going to be spending £1,000s! Just give them a ring the day before to make sure someone who can answer all your questions will be around - after all, they might be flying!