A lot of the items you have there will be available from a decent sized Wilkinsons, who also stock some beer kits themselves.
Maybe also look at getting a trial jar, and a turkey baster. I find these two the best way to remove (turkey baster) and test (trial jar) the beer from the fermenter with the hydrometer.
I dont know north London that well, but its just as bad south of the river for Homebrew shops.
Welcome and good luck.
Newbie just starting out
I bought most of my stuff mail-order from Hop & Grape (www.hopandgrape.co.uk). I can't fault them!