We were talking of the Interarm L3 and 5 conversions on another thread. This is one of their conversions and you can tell this by the barrel configuration. Note on the 3rd and 7th pictures down, the 45 degree angle chamfer between the larger and smaller diameters along its length. This was a quick tell-tale of their barrels. The standard Enfield barrels (and all others) barrels have a distinct radiussed curve between the different diameters.
Interarm barrels, pistons and refurbished breech blocks have the words INT within a circle.