try
http://www.zooplus.co.uk
10% discount for new customers, good range of products and £2.90 delivery charge (free for over £29) - they ship from Germany so delivery takes a little bit longer but I was impressed with the service.
Theres also alot of other places like net *pet* shop, shane tood direct, pets at home and some of the big pet stores on ebay are worth looking at too.
And always have a good look round local pet shops, they can have some really good things sometimes!
*edit*