Which group does he attend? My son goes to New Youth Theatre (based in Mansfield but classes in Bestwood and W. Bridgeford.) He loves it they work towards a show every term (performed in a theatre) and all are guaranteed a part, though auditions are held for the main parts.
They have separate sessions for the different age groups. My son is in the youngest one but the older kids all seem very happy and enthusiastic when I see them.
Proabably not the best if you want classes but very good for expereince of performing, group work etc