There's a lot to be said for keeping your books intact and not ripping them up...
But I don't know why you imagined we'd be chomping at the bit to recommed an area with Western groceries, the Gap, and whatever Talbots is (Especially when Muji goods are a third of the price they retail at in the UK... )

FWIW - Londoners can sign up at www.london-mitsukoshi.co.uk for a store card (free) which gives them 10% off cash purchases at Mitsukoshi stores in Japan - near Yokohama station, Shinjuku, Ebisu and many more.