What I would suggest would be to attend the Professional Flight Training Exhibition run by Flyer magazine and held at a Heathrow Airport hotel each March and November.
Most, if not all, of the training providors attend these exhibitions and it is a good chance to speak to each of them without having to travel the length and breadth of the country.
Once this is done then you can make a short list to actually visit in person to get an idea about the schools you have in mind. Speak to past students, current students etc...
Also I'll second Beagle's wisedom in obtaining a Class 1 Medical and a trial lesson. The first is to ensure you're fit to fly professionally and the second is to see if you actually do like flying!
There are two routes to gaining the necessary licences, one is quicker and quite expensive (Integrated), the other *usually* takes a little longer but is *usually* a little less expensive (Modular). There are many people who post on here who think Modular is the way to go whereas other say Integrated is the only way.
What I say is it is totally up to you. Only you can decide whether to go down the Integrated or Modular route. Each person is different with different circumstances. The licence you end up with is the same at the end of the day.
All the best.