Yes Trident is a great shop and Richard, the owner, is always helpful. He does repairs (some minor ones while you wait if you're lucky!) and he also has a wide range of "OO" and "N" stock in store plus scenics, tools, paints, glue and many other small items. Well worth a visit but do check his opening hours and, in summer, his holiday closure dates. Overall a really great shop and very good service from a very knowledgeable owner/enthusiast.
(I have no affiliation to Trident except as a customer).