Anyone know the quote "that''ll do Randall or RIP Randall" is from? Movie / TV I think it has a gravestone.?

I don't know the quote, but there was an old (possibly) 60s English Tv series called 'Randall & Hopkirk (Deceased)'... and a more recent (late '90s, early 00s maybe) remake by the same name....It was a comedy detective series with two private detectives, but in the first episode one dies and comes back as a ghost and continues in his job helping his partner solve cases. But it was Marty Hopkirk who was the dead one, so I'm probably way off