In reply to The Lemming:
uygher/uzbek music is very good and developed. a lot of central asian stuff is quite twangy and basic, or atonal and lyric based, but the uyghers/uzbeks have complex arrangements for small ensembles yet retain a lot of the essential elements.
afghan stuff too can be very listenable, and of course persian music covers a huge spectrum from nomadic lullabys to full persian orchestras. turkish dervish stuff can get very moving, especially stuff based around the flute. they have a big tradition of riding music thats stimulating listening.
then theres mongolian music if you like esoteric male voices and weird string instruments. string ensembles are incredibly powerful, or single horse-head cello can be very poignant.
god knows where youd find a lot of that tho, but i assume london would have specialty ethnic shops.