Hi Alec, you could try writing to the archivist. The club has patterns for some tank schemes. Other than that, the catalogue gives a pretty good view of where the lower chrome stripe goes.
The Draganfly site gives paint colours, based on UK cars. The usefulness of this depends on where you live.
Some people really like the Wedgewood (Coronation?) blue.
'51,'56 Squares, '48 VH, '27 Model C, R67/2, Mk IV Le Mans, '06 Super Duke and Ariel projects.