This place is definitely on my must see list next time I'm in London. Ohhhh the postage fees that will be parted with.
But, for those travelling from London to France, one little tip is take as much as you can to France with you and post it home from there. Ask for a boite rouge {red box} and fill 'em up. So much cheaper than posting from the UK, and really quick and reliable. My local post office recognised me after the third day, and when I walked through the door, "boite rouge madame?"