I have a feeling this may well be one of the in-Betweeners Joe, that was indeed the cowl that was used in the crossover, and this model was one of the ones in that bracket.
From that, i would put it as 1980 or 1981, Series 80 as Bob said, MKI (There were very few Series 80 MKII engines, and they were later)
It would probably have the last of the G4 carby's, with the face plate familiar to the LM, though it could have an LM, Parts are easy to get for this one.
As to the catcher, I cant be certain, but i would take a strong leaning that your mystery green catcher will happily fit this one.
Fix up the carby, Put a new boot on that spark lead, and there's a good chance you will have yourself a winner.
Can you pop up a photo or two of the carby as it is, so we can see whats missing?
