I agree with FNG/FFF re the importance of an experienced instructor. If possible, try to find one who has owned his/her own tailwheel airplane, or has done glider towing or bush flying (I guess the latter would be unlikely in England!). That way you'll know that they have bags of practice handling "conventional" undercarriage in a variety of situations (especially strong crosswinds).
BTW, there are schools out there purporting to give complete tailwheel checkouts but they won't rent the airplane solo after the training is done. Seems to me that they're not confident enough in their instructors' teaching ability or judgment re solos, so it is not really a valid checkout and I would go somewhere else.