Shortbread is always readily available in grocery stores in England. But at Christmas, it comes in tins and becomes super cheap.
Among the things England is missing out on are popcorn balls. If I could find the lid to the giant pan I brought with me from Alaska, I'd get right on introducing my own personal English people to them. I'm not convinced that Golden syrup is an appropriate substitution for corn syrup in this case, but it's worth a try.