My sister's flat has two markets Tescos (the one that had all the horse meat when it said beef) and Waitrose. I love waitrose it's more high end than Tesco but their prepared/packaged foods are SO good and they have some good vegan stuff. Sadly their alt meat has eggs in it. Here are some things I really liked (it's all Mediterranean food):
I also found gf/wf wraps that are really good! They have a gf section but it's really small and not that exciting.