I never see Suffolk mowers here in New England USA but would love to try one! Great video!

Being in the colonies, we got all the export stuff as you might imagine. My Morris minor has a dusty road oil bath air filter rather than the steel mesh that the UK got for example. Generally stuff like exhausts and air filters I find to be different on many small engines. But it extends to Japanese imports as well, my mitsubishi ute has different steel pressings in the tray. And sometimes the paint and interior of things are local market specific. All because of import tariffs, a certain percentage of things had to be made local to avoid large taxes on imported goods. Also why things were imported as CKD complete knock down kits to assemble here. Keep the locals working

Regarding the date, I think 1975 is certainly very close. I have a similar '72 brochure (not accessible right now) but from memory everything looks about the same. I believe that by the later 70's the plastic air filter was being used. I have a 12" model that was purchased many years ago from the original owner who said he bought it in 1976. That looks identical to the brochure other than it had a plastic air filter.