Charlotte, I got both my Axies from Webbs in Wychbold (just south of B'ham). They often have a good variety of Axies in stock. They arn't overly informed though, so be prepared for a few blank faces if you ask some in depth questions.
I was really disappointed with Shirley aquatics. They had about 15 half sized Axies in one small (3ft) tank. It was really cruel.
Another good place is Midland Aquatics in Bromsgrove (just south of B'ham). They don't have many in the shop, but normally have dozens out the back as they are a wholesaler for a large part of the UK.
If your interested in any of these stores, let me know and I'll post directions or links.