Graham,
The styled 25 you have just posted reminded me of a very similar tractor (if not the same one) which I saw at a small club museum near Moose Jaw SK back in 1996, there was some intersting Wallis tractors at the same place too? I must dig out my old photographs.
Another tractor with the Robin set up plus the additional oil filter / heater fitted which seemed to be popular in your part of the world.
I see the styled 25 which Nixon's sold on Saturday at the Seger Estate sale in Johnson Kansas sold very well at $3100.00, a pity they did not post the serial number, so hope there was a Massey collector there who noted it for your list, maybe it has gone to a good Massey home?
Malcolm.