Wow...that forend cap job looks pretty well done. Never seen such a combination of parts. The barrel looks to be the original LB one, has 43, C Broad Arrow and DCP(Dominion of Canada Proof) on it.
Someone with skills built this rifle.
Does that make it valuable? Theoretically no, but it seems people like what they are seeing. As a curiosity and a nice shooter it might be worth more than the normal sporter amount.
At first, the quasi-Jungle Carbine forend made me think it was one of the "Royal Marine Commando" specials...but too much else is different than the pattern for those.