Buns have always been small cakes to me. "Cup cake" is a relatively new term to me which I had thought was American. The difference between these and buns seemed to be to be that the "Cup cake" was slightly larger. I was about to say that the cases in the cupboard agreed with this but on checking now, I see the smaller ones are described as "Fairy cake".

Some people, including my mother use "pikelet" to include what I call "crumpets". Going by this page, this usage is found in the Midlands and Yorkshire in England. Mum is Shropshire (West Midlands).