Translation - more rhyming slang, although not necessarily 'cockney'
Lady Godiva - 'fiver' (£5)
Ayton Senna - 'tenner' (£10) - obviously a more modern idiom.
I have not come accross a Commodore before so am going to guess because of where it sits in the list as £15
Score - £20 (as in three-score-years-and-10 and all that)
Pony - £25 - some latin root in there - that is an old one.
I don't think they are dying out, in that paying a pony is still £25 with cash or with a card.
Sadly, I think these are dying out due to the move towards a cashless society.
The most common use for any of these (for me) was to ask someone to lend me a bit of cash when I'd left my wallet at home.