So one of the mowers I had to wait a long time to go and pick up is my 1974 build Sunbeam 160cc low arch.
I just gave it a very basic clean off yesterday and took some pictures. The engine case says it's a 74 build and it's got a G3 carby on it, so that all lines up.
Anyway here are some pictures of it and its immaculate catcher, also the serial number and pictures from my 75-76 dial a code with my exact mower except the Carby in the dial a code picture is G4 and the fuel cap is in a different position, otherwise it's a very very close match...