Newbie Request: Russian stamp selling (in the UK?)

Hi
I have a large amount of very good condition old Russian stamps (some
unused and dating from the start of the 1900's), some in blocks, some
collectable editions etc etc. I am looking at selling them, depending
on their value. Is there any place (aside from ebay) that is
recommended to sell such items? I am in the UK but any online or real
stores (in the London area) would be a good start as I don't really
have any guidance on how to proceed. Any help is better than nothing!

Thanks guys.