Snail and Mo islam are correct.
THE best FC gym is the USKA , Bar none!!!

The subject is not open to debate.

Reasons for that is:
The fighters coming through the door are:

1.they are young and hungry and from a rough part of birmingham (the same city where 4 people shot dead in a pub doesnt even make the evening news:P)

2.They all have tidy boxing

3.They have a close knit squad and all seem to be good friends as well as teammates (team work is important)

4.They are superior to other FC gyms with kicking.
Most FC gyms dont teach people how to KICK!!!
in too many FC clubs they just throw the leg their body mechanics are incorrect . (i couldnt be bothered to go into details, it would take me forever to give a detailed explanation of how the axis of power works and angles of attack with the correct angle of bending the leg.,..etc)

Basically, USKA kicking is :
Muaythai roundhouses + The flair of TKD kicking ( chances are that the grading syllabus is emphasised strongly too which does help in acquisition of kicking skills)

5.Like dale said they do the light contact and amateur circuits and that pays off

6. Being taught by an EX champ and the strength of coaching doesnt harm things either ;)

The above are all equal factors. Good coaching alone is not enough