Then there's the occasional one that's still around. Like Fuller, Smith & Turner.
Let's take a look at their beers, shall we?
London Pride has been around in its current form the longest. I'm not sure when it was given that name, but I'm pretty sure the 1951 Best Bitter is the same beer. You can see how their Pale Ale (or Bitter) was emasculated during WW II, dropping from 1050 to a puny 1032. In 1959 it managed to have an even lower OG than their Mild. I assume that London Pride was introduced around 1951 when government controls on beer gravity were loosened. Many breweries took the opportunity to re-introduce a stronger Bitter, though not at pre-war strength.
Why doesn't ESB appear until so late? Because it wasn't introduced until 1971, when it replaced their Burton (Strong Ale in the table). Fuller's Mild, by then called Hock, was discontuinued as a regular beer in the early 1980's. A shame, as it was rather nice, when you could find it. Mild had already pretty much disappeared as a mainstream beer in London by the late 1970's.
Groves & Whitnall
Red Rose Stout, September 3rd 1959:
Bought by Greenall Whitley (spit) 1961 and closed 1972.
There's also a Groves & Whitnall forum. The mere knowledge of its existence brings a smile to my face.