Vintage Horticultural and Garden Machinery Club

Well,here goes,the first engine that Power Specialist used was villiers,A Bux is a villiers under license to Power Specialists, in the first couple of years,then part of the licensing fell away,so that the latter ones,had different parts attached.
A nowadays term for these engines could be classed as badge engineered
You mention Ransomes,They have a long history of badge engineering.
The first engine which was badged was the Simms way back in 1905,this became the Orwell (derived from the river that runs through Ipswich.)
I suspect the engine you are talking about is the Ransomes 4 stroke which appeared on the Mk 10 Motor Mower or on the MG Tractors.This engine was originally a Sturmy Archer,then a license was bought by Ransomes.
Ransomes also badge engineered binks carburettors.
To give another licensing exercise
Atco
Chas H Pugh made under license,Senspray carbs, and also Claudel Hobsen carbs
Hope this clears your head
Kind regards
Andrew hdtrust