I'm taking 10yo DS to London at half-term and this morning he asked if there's a big/cool sweet shop we could visit. I know there's all those American candy shops but they're a rip-off - he's picturing more the old-fashioned type of sweet shop or just something with a big selection. Not M&Ms World! Preferably somewhere where a 10yo with a fiver could come out with a reasonable amount of stuff.