Below are some store links that I personally recommend. To appear in the list the stores must have met the following criteria :-
Good telephone manner.
Assisance over the phone resolving problems.
Quick e-mail responses.
Easy to navigate online store.
Quick notification of Out of Stock Items.
Easy Returns procedure.
Overall a service that exceeds expectations.
Currently there are only 3 fly tying / fishing sites that I have found in the UK that meet these criteria and that I am happy to recommend.
Started in 1993 at JUBILEE LAKES FLY FISHERY, THE ANGLERS' LODGE has become one of the largest & best stocked specialist game fishing shops in the North of England
Providing high quality saltwater fly fishing products, guided UK Bassfishing and escorted fly fishing trips around the globe.
Fish4ituk provides the Fly Fisherman with quality fishing tackle and fly tying materials. They also have a customer loyalty discount. ie The more you go back and purchase, the more discount you receive. What you see on the site is what is in stock.
Lakeland flytying sells fly tying equipment, rods and reels. It has a very good online store which actually gives stock levels of each item. They are very good at advising when they expect items in stock again.