CONaries-agreeed loved that box of 'treasures'
Dress Circle can be more expensive, particularly for the more 'mainstream' stuff you can pick up in HMV/Amazon etc but it's one of the only places to find the more unusual stuff.
They have a great selection of books/sheet music as well.
I've lost a lot of time in there from browsing to chatting with the lovely staff about what we'd seen reccently-one of the many things I miss about living in London is Dress Circle!
Maybe I'm on nobody's side
http://phdconfessions.blogspot.com/