Those tins of Heinz Salad where also a thing in the East Midlands too. We had an instinctual mistrust of vegetables that weren't tinned or required several days of soaking. I remember the occasional tomato. I presumed it had got lost.
Just to prove the entire 70s and 80s weren't entirely prepackaged or dehydrated (mmm, space food), we did have tinned salmon on very special occasions, mixed with butter. Only very special occasions though because it was by far the most expensive thing in the cupboard.
Salmon sandwiches was definitely one of my favourite foods. The other meal, and the first I learned to cook, was fish fingers, instant mash, frozen peas and packet parsley sauce. I used to come home from school and make this for myself and my sister, back in the days when it was fine to leave your kids to fend for themselves in front of a hot cooker.