My selection of 3 Top London Wine Merchants for finding the best Under £10 wine:
Lea and Sandeman
(SW10, W8, SW13, W4)
Boasting 114 wines under £10 on their site these neat and tidy, established and highly regarded shops excel in quality value wine from the old and new world.
Albion Wine Shippers
Spain currently makes some of the best value wines which, along with Southern French (and Mexico), is where Albion excels. That and dust, odd bottles and organised chaos.