Trying not to get too far ahead of myself, livestock wise I would probably be looking at Aquahome at Avant garden centre near Leyland golf club and Maidenhead Aquatics in Broughton.
The shop at Avant garden centre, a friend of mine uses and has said the customer service is good, but when I've been in, the shop has been a bit hit and miss appearance wise. You should never judge a book by its' cover though!
Maidenhead Aquatics, I can say that it looks a good shop.
Tank, sump, equipment etc. wise, I haven't chosen the bottomless pit I will be pouring my money into yet!