Hi RobD,
I have noticed many commercial long lee pattern rifles of commercial manufacture often have the SMLE style buttplate and sling swivel/base. I have two other long lee's in 303. Both are commercial BSA guns, and they both have these SMLE traits. I have no idea why this is, other than perhaps cost expediency. On this last photo, you can see the stock does not have a cutout for the SMLE safety.
I also have a commercial LE carbine that has the long tang buttplate found on the MLM's and MLE's (a trait not seen on military issued LE carbines). And, the buttstock is serialized to the carbine (on the wood hidden under the butt-socket), so I know it's original to the carbine.
Any guesses out there in forumland?