I was a market trader in London from the late 80’s to early noughts. Not a native cockney speaker, as it were, but necessary to get business done on the trading floor. 5 (lady) and 10 (Ayrton) are good, you need to add a “horn” for twenty…rhymes with horn of plenty.
I also see you have “ton” down for 100. You are only partially there. We would trade a “china-man”, as in wonton…100. Don’t ask me to be accurate in the translation. Yes, it would have made a bit more sense for china-man to equal 1000, but that’s not how it was/is used. A china-man is 100 units of whatever you are discussing/trading.
Also, never heard the term spit roast, but I love it…both very clever (takes real math, mate) and sort of dirty/sexual at the same time. Love it, 2 ayrtons and a lady, beautiful imagery.