Yes, sprinkle the vinegar on both and/or put in a shallow bowl for dipping both the fish and chips. (And I think you are supposed to eat the fish and chips with your fingers, not knife and fork).)
“(And I think you are supposed to eat the fish and chips with your fingers, not knife and fork).”
Maybe, but I’d really get the stares in Victoria when I’d pick up fried chicken that way. I do not recall how it was done in Southampton as I was only 17 at the time.