Thanks for the replies! I may have to try them all to see which one I like best...

I've been in London for the past 3 months and they don't even know how to pronounce guacamole, much less make it! I'm looking for someplace good and authentic. I can go for anything from a hole-in-the-wall to a proper restaurant. Thanks in advance since I know I can count on the chowhounds to point the way.