Yes, its Enfield Mk.I body BB4135 (1943).
I think that barrel is british Mk2, butt slide is Mk1, body is for sure also british Mk1, but confused about bipod and butt. If the bipod in canadian one, its more mixed I expected...
Butt looks like Mk2, but what about the straight butt plate? I would expect the curved one
And finally Mk2 piston inside...
What about the sign JI hammered on the parts? Is this mark of particular company?