Thanks, Canary42, for your reminder of The Golden Egg.
After a night out in Sheffield city centre in the first year of my student days, a visit here was regarded as essential:
https://tinyurl.com/y8rxbo85
(They were open 24 hours per day but, unlike the rest of the day, you had to pay for your meal when you ordered it late at night).
Sadly, The Golden Egg in Sheffield shut down well before I completed my studies. (They were probably fed up of drunken students!). So we had to resort to finding late-night chippies open instead.