We tried a dozen different shops, pretty sure one was Marks and Spencer. I remember one had a big green sign with white or yellow letters hahaha. Not like it helps
I was joking with the "tasted like shit" part We were mostly surprised because we couldn't really find some kind of shop where we could buy ingredients, like a "normal" supermarket over here, and in most other countries I've been to. The groceries-shopping experience was definitely different from anything I expected. We really liked London though, don't want to sound like it was a negative experience.