Hello Charlie
Its made by Suffolk Iron Foundries whilst hard to see in your image look above the ‘I’ in PERFECTION & I you will see the SIF logo. Not seen one of these but its virtually the same as the Suffolk ‘Eden’ first produced late 1930’s, I have seen parts list for the Eden 1947 which has exactly the same distinctive handles as yours.The Perfection & the Eden both appear in the 1953 Suffolk catalogue with crossover tubular metal handles.I have 2 Edens both with Pram handle, but they appear to have been produced in 4 versions, straight Handles, Pram, Cross-over & same as yours.
So your perfection I would assume was just post WW2. You have a nice mower there with good original transfer. Hope that helps.
Regards
Clive
The Budding Foundation/ Museum of Gardening