Hope Britain treated you well overall, Matt. I bet I know which guy in Dave's you mean. Yeah, that guy. Next time I'm in there, he's going to get the frowning of a lifetime!
I now get my comics from Millennium Comics in Nottingham. I live nowhere near, but the postal service is first-rate, and the customer service unparalleled amongst all stores I've been to, even including my old, closed, beloved Travelling Man.
If you're in Nottingham, give Millennium a try. I doubt they'll disappoint.
Forbiddon Planet is good :] If your in Leicester (im not sure if they spread further than that) Magic Labyrinth is good, but a few members of staff patronised and rushed me out with fast 'no we dont sell that's as quickly as humanly possible
I've been to the Bristol FP most Saturdays in the past few months and never had any reason to complain about it - generally it's a nice shop and I like the staff. The reason I chose it over TM was that although the staff were good and I could usually find what I was after, they charged extra for alternate covers. Seeing a copy of some issue of Civil War on sale for ten quid confused me a bit, and I didn't go back many times after that. I've forgotten the point I was trying to make.
I'll chime in and recommend Gosh! as well (got my pull list there) - excellent small shop with nice staff as opposed to FP which is more like the Tesco of comic shops.
There's also Krypton Comics (quite far out of the center) http://www.kryptoncomics.com/ They're more of a mail order shop but they have an enormous amount of Marvel/DC back issues going back to the bronze & silver age.