Originally Posted by Fraghead
The only places I can think of that sell niche in the UK are:
and my online fragrance shop of choicewww.audliebezumduft.de
Great selection, and although they are based in Germany, orders are delivered with about 3 days.
This, and I'd add Liberty. Also, Santa Maria Novella has two shops in London, and Parfums de Nicolai has a tiny boutique in South Kensington. Diptyque can be found in Space NK, and you can also find brands like Tokyo Milk in John Lewis (it's not with the rest of the perfumes; it's near the candles) and Histoires de Parfums at Anthropologie.
A really well-kept secret is Angela Flanders, who makes her own perfume and sells it in her shop in Shoreditch, which is open only on Sundays from 10am - 3pm. She also sells through her daughter's shop, Precious, near Liverpool Street. Some really nice scents and not extremely expensive.
I think you can order online for most of these, and I vehemently endorse audliebezumduft.de (First in Fragrance).
Finally, I was just talking about these in another thread, but there are some really good cheaper perfumes out there that aren't very well known, that you can find at Cheapsmells.co.uk or FragranceNet. Like Jacomo Silences, Lancome Cuir, Tabu, etc.
A trip to London may be just the thing for you, though. Book well in advance and the train is very cheap!