We have antics, they do all models, plastic kits of boats, planes, cars etc aswell as all rc stuff (part of anticsonline theyve got branches elsewhere), that's in the city centre, then in st George there's Model mania, not been in there for a long time but they used to be more for trains.
Not sure about any others.
Tbh (I'll probably get a flaming for this) but I'm surprised no one mentions hobbycraft, I get all my paints, brushes, glues and some good price kits from there. Got a 1/400 tirpitz kit for £14 this week, hull is hard to glue together but I never find airfix kits to be good quality.