Yes, I think it ran like this.

The original Queen was the Model 16 (c1950).
It came in two sizes - 20" & 24" - and was sold in petrol (Villiers) and electric
versions (24" only). Its application was general or specific - depending on the spec.

The Model 30 Queen (c1958) was a specific design - for bowling greens.
It was 30" and only came with an electric power unit.

My guess is that the Model 16 was discontinued when the Model 65 came on-line.
The Model 65 was made available in 24" and 30". These had power plants that
were only petrol, and these did include Honda engines.

This is Grant Simpson's schema of the SB Queen models:
[Linked Image]

Hope this helps.
----------------------
Jack