Back in the early 1970s, I spent some time in the UK.
The fast food there was seriously dire.----Aussies, Yanks, Kiwis, & Canucks would get together & whinge about it.
Even English Fish 'n' Chips wasn't as good as I expected----the quality in Scotland was far better.
In Southampton, there was a roadside burger van I sometimes attended.
The burger "patties" were slices off a sort of big sausage, the onions were half cooked, & the buns soft.
I once drove 70miles to London to buy KFC, but it was a bit cold, & served with chips, which I found weird.
( KFC in Oz didn't do chips back then)
From what I've heard, fast food has improved out of sight in the UK since those far off days.