It is quite possible that the engine could have stayed in stock for twelve months or more, either in stock with the manufacturer or with Landmaster. There are some large discrepancies with the Trusty numbering, and it is probably down to the factory “Doing a deal” to buy up any old stock that may be hanging around at the engine manufacturer’s.
A great case in point is the distribution of Norton engines. By looking at the numbering it looks like a large batch of engines (probably war-surplus) was bought and put on the shelf to be used over a prolonged period.
Don’t always use the engine number as gospel- it is a good starting point if nothing else is available, but it can be misleading in such cases.
.
