I got some in B&Q last year, they were chrome though and not cheap but were a 'must have for the job' item.
They do..or did (not been in since) have a massive range of window and door handles etc.
How many do you need and are you looking for an exact match? Not that long ago I came across some brass ones left over from a flat we owned years ago, I will have a look see if I can find them this evening.