It looks like I have a Mayfair utility like the one from the brochure.
No idea if you can work out the date from the 1980's engine numbers, Victa Commodore 160cc No.02000383, Victa Goldline 125cc No.020002114, Mayfair Utility 160cc No.02000941
I was told the last number on the head is the year code ,you must know the right decade of the mower first so in the black and white image of the head, 207 means the year is 1977.
The head code on the Goldline 125cc is 020 that means the year is 1980 that's if this system is right for working out the year code.
The code on the Corvette is 270 .... 1980
The code on the Commodore is 280 .... 1980
I would say the numbers are stamped when the complete mower is assembled.
I like the different looking Victa mowers like that Sunbeam,I haven't noticed that one before now.
Here are a couple more different looking Victa mowers in the below pics, Sunbeam Super , Super V MK III.
Some Goldline mowers may have the 160cc engine.
The Young's ad image shows the Victa Mayfair 4 stroke on a High Arch base.