In the original script, the character's name was Paradiso. I assume it was changed because Paradiso sounds too Italian for Billy Connolly to play, but why Findlay Crawford, or whose idea that was, I never knew. It sounds like you have solved that question!
Billy Connolly did a sketch where he mocked posh Scottish people with second names as first names "Crawford, have you seen Findlay?". When he was asked to suggest a name for his character he used those two names as the character was a posh Scot.