White Castle also isn't present across most of America either. Subway is the largest fast food chain in the world so it would be more interesting to hear what sort of presence they have.

Subway are everywhere in the UK. Having colonised most town centres they’re now popping up in garage forcourts (service stations).

To be honest, it is far from clear that these commercial burgers are anything remotely like meat. And not sandwiches in our lexicon, certainly, no more than these shops are anything like restaurants. They might be food-like substances, rather. https://www.webmd.com/food-recipes/news/20090323/7-rules-for...

While McDonalds wasn't widespread there were regional burger / fast-food places around in the UK at that time.

For example I had a small birthday-party, which I still remember fondly, at a Wimpy burger-place back in 84 or so.

I certainly remember Wimpy, it was great back then - you got your food on a real actual plate :)

Something which is disappearing at the high and the low end of the market these days!