WANTED: LATIN Cds - Where to find decent stores in LONDON

[Mike]

When I browse at the incredible Descarga.com – Shop on the internet, I always realise that most of the really interesting CDs are not available in Germany (unless you have a credit card – and I haven´t..)
As I´m going on a trip to LONDON in a fortnight, I thought maybe there are some good CD shops around where I might find some "rare" Latin CDs. I´m not really familiar with the record stores there, so help of any kind is greatly appreciated. Thanks!