I've got many happy memories of going down a dark alley in my town back in my teens, there was a little shop at the end of it called Console Mania that did all the consoles, part exchange, accessories and imports
We bought so many games from there, and I was quite sad to see it go in the late 90's, they had things like Action Replays, all the multi region adaptors, the floppy disk add on for the snes that let you pirate stuff, and a very early Japanese import of Street Fighter (turbo edition i think?) for ~£95 pretty much the week it launched, as well as things like early saturns/dreamcasts, a neogeo etc.
I've still got the big fully metal fighting stick I got from there somewhere in the loft.
There was another shop on IIRC the outskirts of Hemel that I used to go to and they did older PC games and hardware, we bought so many games for the 386 and 486 there.
There was also a little shop at Shenley Church End in MK that we'd go to on a regular basis in the 486/pentium days, I remember walking in one day and seeing Warcraft II running on the demo PC and promptly buying a copy of it.