Check out www.greatamericansports.co.uk. You should remember it from it's days in Birmingham. One of the first American football retailers in the country has been revamped and relocated to sunny Devon. It's a great looking website, which has a great selection of NFL gear from jerseys to jackets. You can order the jersey of your choice from them using their bespoke service. Reasonably priced and great choice, make this one, your first choice!

I got a SB champs t-shirt and terrible towel from them, good website and friendly. An excellent birthday present for myself =D

Some of the jackets and tshirts appear to be a bit dated although they do a great job bringing NFL products to the UK.
I remember going to the Birmingham shop a few times!!