I'm not quite sure why Paulb52 would ask a question on identifying an engine and then lock it so no one can reply but with my level of computer skills I know I could easily do the same and not know it so I can't sneer at anyone else.
Anyway I can tell Paul why no one can identify his Villiers engine and that's because it isn't Villiers. It is a Triumph Model X, a 174cc unit construction two-stroke with a 2-speed gear box built in. Made between 1930-32.
Triumph reduced the bore in 1932 to reduce engine capacity to 149cc for even cheaper road tax. They then called it the Model Z but it only lasted that year.
Times were tough, very tough, and factories were doing whatever they could to survive. These models are part of what Triumph did. They are worthy of preservation even if just to show how factories fought to stay afloat.
No reason why it shouldn't run quite well but the 2-speed box is the great limitation.
Cheers,