I think I saw that one at the OGCA show last month.
I was tempted but have too much to do now!

Looks like an SMLE bbl in place of the heavier MLE/MLM contour bbl.
They have the same thread,,same thread timing, the extractor cut is usually rounded on the later SMLE bbl,,squared bottom on the MLE/MLM bbls).
Birmingham proofs.

I suspect a cut down Military forend.
IIRC the butt stock was a Military style with a checkered grip on the rifle I saw at OGCA.
BSA did offer several styles of 'Officers' carbines for commercial sale using the military style butt stock w/checkering and better quality wood.

There should have been no side safety lever on these MLE/MLM rifles to begin with.
The blank cut out on the left side that is now empty was for the rear volley folding sight staff on the original Military rifle.
The forend was cut for sporter just to the rear of the front volley sight plate to elliminate that feature.

Safety on the Metford was the half cock notch (though the very earliest did have a side lever safety that was deemed un-necessary and quickly done away with).
Safety on the MLE was on the striker knob itself. A thumb activated lever.
The SMLE (re)introduced the left side safety lever.