I think the Rumpo songs were mainly written by Barry Took - although it was Kenneth Williams' genius to make the character what it was.It wasnt polari in the songs - Took says they just made up a lot of the folkie lingo.I also get pissed off with people caricaturing folk as "hey nonny-no" - just pure laziness - but often Sid Rumpo (slang for "a leg-over situation" according to Took) does get a bullseye with a certain kind of fake folkie.We had a Sid Rumpo here in yorkshire many years ago called Walter Greaves - an admirable man in many ways, but a complete phony as a singer.