I've recently acquired an early 14" Punch that having read Ian Wallis's article in Grassbox edition 90, I believe that it may be a model 1 or 1a from dating from 1954 -56.
The identifying points are as follows and may assist with a more specific date.
Exposed cylinder head and partial engine shroud.
Rope wrap starting pulley - no recoil.
Black painted cylinder block and unpainted sump.
The knurled main jet adjuster for the Zenith carb' is drilled and there is an adjacent small cast and drilled lug on the carb' float chamber - presumably to take a locking wire to deter unauthorised adjustment.
No dip stick of any sort. If it ever had one of the split pin type the drilled plug has been replaced with a plain one.
Individual left and right height adjusters, no single point micro set screw adjuster .
A pedal cycle type free wheel mechanism in the land roll drive - no dog clutch.
Restore, or clean and preserve?
On the whole the original paint is probably 60% present and , in particular, the Suffolk transfer on the chain case is in good condition . I think the "red" on the engine shroud and fuel tank is original but possibly faded . Does not appear to be the "red/orange" of the later machines.
All thoughts and observations welcome!