Speed-Lee markings

[Jc5]

A commercial Lee Enfield would use whatever bayonet that its closest service pattern relative would use. The trade pattern and officer model carbines used a bayonet mount similar to the ones on the Long Lee rifles, which would take the 1888 bayonet. Later commercial Lee Enfields based on the SMLE would take the later bayonets. However, yours doesn't seem to have a bayonet lug at all! Could you post a close-up photo of the nose cap?

BTW, the term "Lee Speed" is really just shorthand. There was never a commercial model called a "Lee Speed." The stamp is an acknowledgement of patents, not a model of rifle. We all call them "Lee Speeds" but that just means it's a commercial rifle that has the LSP stamp on it. Plenty of commercial rifles lack the LSP stamp, being produced after the patents had expired. Even Skennerton (in his book) uses the term "Lee Speed" to refer to rifles that lack the LSP stamp. Others will disagree with nomenclature, and that's OK.

I also spent some time looking up markings with no success. The script looks similar to Ethiopian characters, but no exact matches.

The rifle is definitely a commercial BSA, but it was likely a private purchase rather than part of a contract. I don't know of any large contracts for these carbines.

Is the serial number stamped on the top-rear flat part of the action, where the bolt slides in?