Barry - since it's presumably done through your union, it'll almost certainly be PSM or ADM. The latter are a lot better, certainly in terms of getting the size right if nothing else. Might be worth investigating whether your Union has an exclusive supply contract - I know York signed one of these two years back that gave all the business of every sports club and union society to ADM for three years, and the discounts were phenomenal.
15 quid sounds about right, I'm used to paying 20 for mine with a custom screenprint. For fleeces etc would suggest you have a gander at whoever your Union supplier is, if they have one. Otherwise, see what Tesco have and nip down your local T-shirt printer, they frequently do discounts if it's large orders.
