Gidday Jack Yes I found an ad for a SupaSwift Pope (1974) but had not seen any surviving mowers.
The brochure you have Jack I would date , 1970-1971. I have looked at that brochure many times, thanks for uploading better quality images of that document.( I'm sure you have seen the date on the document before and forgot it was there, it's in the right hand top text.)