I've just picked up on this thread, which is a particular interest of mine.
Congratulation, Rod, for a masterly transcription of by's wonderful rhyming narrative.
I have one disagreement with you, which is ove "... on his Jack ..." The rhyming couplet is Jack Jones = alone, which is of fairly modern provenance (ref to Jack Jones, the Trades Union Leader.) b-y could have used, " ..on his Todd ..." for the same meaning; I am not absolutely certain of the provenance of this one, which is far older. I think that the couplet is Todd Malone = alone, and he was probably a sportsman (prize-fighter?) in the mid C19. I'm at work, so can't look up my prize ring references, but it certainly rings a bell (sorry!!)
BelM inmplied that it was a war-time camoflage of language, but it is very much older than that, probably dating back to the C18, certainly strongly in use in the C19. It's purpose was to allow the costers (= street traders, or "barrow-boys") to converse without either the "punters" (their customers) or the "rozzers" (= peelers, bobbies, blue-boys = police) to understand what they were talkong about. Essential when you were a) taking advantage of your customers, b) dealing in stolen goods = probably both at the same time!
As you will have noticed from Rod's transcription, not all of the words are rhyming slang - there is a whole lot of thieves cant and Romany words in use as well (e.g. karsi, which is a Romany word for the area beyond the caravan where you go to relieve yourself.) When spoken fast and in a strong East End accent, it is impossible for an outsider to break the code - not least because the rhyming slang changes frequently.
