Thanks for replying. Not sure how to download pics. I did a bit of research. Alloy head with eight bolts. Models 17/19/22 ? Also logo fits between 1976 to 1985. Rotavator has not been running since late 1980s I think ? One interesting thing the fuel tank, pick up and carb are in excellent condition. Not like some old motorbike tanks I’ve seen. Might be something to do with leaded petrol !