Four small things I miss:
Irn Bru. Soda made with ammonium ferric citrate. Tastes like a mixture of rust and bubblegum. Allegedly very popular in Scotland.
Kellogg’s Super Noodles. Yes, you can get ramen, but it’s not the same. For instance, you don’t generally get Indian curry-flavored ramen…
Toasted tea cakes. Please don’t ask me to describe what these are like; I’ve tried, and I lack the expressive power. Go to England and try some.
Pickled onion flavor Monster Munch. Potato snacks shaped like monsters’ paws. The ‘pickled onion’ ones smell like developing fluid and taste like battery acid… but in a good way. Also, they leave your breath stinky for hours.