The best anecdote I've seen about him/by him, no idea if it is true but it is funny from a Gareth Roberts:
My favourite John Savident story (and there were many). As I recall it, as he recalled it to me during my Coro St days.
He was stocking up on some Christmas booze one year at a posh off license in the West End. Ahead of him at the counter there’s a woman placing an order. John S thinks, ‘oh damn - I’m sure I’ve worked with her in something, but for the life of me I can’t remember what, or even her name.’ So he tries to strike up a conversation - ‘Oh hello, my darling, lovely to see you again!’ - bit of actors’ chat.
She’s polite but a bit icy. ‘How’s work? Doing panto this year?’ he asks. ‘No’, she replies, with a bit of a stare.
She heads off. John Savident thinks, oh, bit toffee-nosed her, wish I could remember her name and what we were in together, I know that face so well …
A moment later the penny drops.
‘Oh God. That was Princess Margaret.’