If you come to England, I recommend trying Cadbury's or Thornton's chocolate. In my opinion you can't go wrong with them. Since you say you're visiting Switzerland, Swiss chocolate is supposed to be very nice too, so if you haven't tried it already I would recommend you to try some.

Also, if you visit England, be sure to try our most traditional meal of them all... fish and chips! With a bit of malt vinegar and some mushy peas. Delicious. Oh, and brown sauce... HP brown sauce (not with fish and chips, but just in general). Leor had quite an experience trying them while he was here these last couple of times, and I must say it was amusing to see what his reactions to them were. But this time he went home with quite some things they don't sell in Mexico, so I know he approves well of them.

I'm trying to think of more, but I can't remember them right now... xP