BSA Lee-Enfield removable .22 conversion kit

This thread was posted by Promo in "The Lee Enfield Knowledge Libraryicon Collectors Forum". We both have this rare BSA .22 Long conversion kit for the .303 Pattern 1914 (P14) Britishicon service rifle.
We can't find any information about it. Maybe someone in the ".22 Smallbore" forum knows more? I hope someone can help. All information will be greatly apreciated!
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