Malcolm Tanner in the television adaptation is actually Alan Bennett (the famous author/playwright) in the Nina Stibbe book.
The character of Georgia is based on Mary-Kay Wilmers, editor of London Review of Books and former wife of director Stephen Frears.
Gloucester Crescent in North London is the same setting, around the same period, as that of The Lady In The Van (2015). Both feature characters based on Alan Bennett and Ursula Vaughan Williams.
The character Max is based on Sam Frears, who plays Ray in this dramatization of part of his childhood.