You don't have to turn this one into anything, friend; that's pretty much what it is.
"LEE-SPEED PATENTS" was marked on COMMERCIAL Lee-METFORD Mark II rifles, including vast numbers for various Yeomanries, Militias, Territorials, Volunteers, Fencibles and so forth They were made as paramilitary rifles, military rifles and as sporters. Following the Great War, they were declared obsolete and so were sold off, largely through the gunmaking Trade.
Once the Trade got their hands on them, anything went, pretty much. I have one here with markings only on the barrel itself; receiver has been scrubbed. On the barrel, though, are very nice things: a tiny little triangle with the words "A.G. PARKER" and "BISLEY WORKS" and their own serial number, which is 0019. Barrel is 23 inches (as opposed to 30.25 original) and the front sight bead is Gold, which the Army NEVER would have paid for. I have a letter from PH on this one; they told me that they would have done it about 1920. Mine, as yours, has remodelled military wood, although mine has been commercialised a bit more than yours (long-ange sights removed and the holes in the fore-end plugged with bits of wood from the chopped fore-arm.
You have a very nice chunk of history, friend. The old girl likely saw service in the Second Boer War and the Great War both.
BTW, rather doubt that your SUPERIOR NICKEL STEEL would have been available much prior to the Great War, so this dates her. Nickel steel was regarded as very much an innovation in the P-'14; it wa not that popular for some times because it was 'sticky' as compared to glass-hard case-hardening.
Any other markings? What about Proofs? Mine is Proofed for the 215-grain bullet and a case length of 2.21" rather than the 2.222" usually seen.
What type of rifling? Original to mine was Metford: 7 grooves segmental, 1 in 10, lefthand. Original rifling for yours should be Enfield: 5 grooves, lands and grooves equal width, 1 turn in 10 inches, lefthand. Mine NOW is Parker's own idea of rifling, which is NOT what the military specified; it is their own barrel. Your barrel is BSA? Your receiver is Enfield: proof that the Trade had their mucky little hands in her guttiwutts.
Nice rifle!

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