Is this a BSA?

[Bobo W]

[nicanary]

The thin strip down the centre of the radiator shell suggest it is.

[Allan L]

. . . and the Motometer suggests it's not the air-cooled V twin but the water-cooled four-cylinder version.

[Perseverant]

Definitely a BSA. Did the four wheel ones have similar mechanics? I also wonder if the Stirlingshire registration is original?

[Allan L]

Perseverant said:

Definitely a BSA. Did the four wheel ones have similar mechanics? I also wonder if the Stirlingshire registration is original?

The Scout had the same machinery as the four-cylinder trike. I think the V-twin was three-wheeler only.
We can't see a reg. in the OP's photo and nicanary's is just one he's found on the web at some time.
When did Stirlingshire go to three letters? YWG must be a good few years later and I'd guess it's post-war.

[Allan L]

Just to tidy this a bit, here is a BSA V-twin trike for comparison: