It's a genuine No5 & made at the Royal Ordnance Factory at Fazackerley, Liverpool, UKin August 1944, the first year of manufacture (they were made from 1944 to 1947 inclusive). However, I don't know about it being unfired. It's possible, but I doubt it judging by the wear to the finish on the metalwork. The wood has also been sanded - you can see it has been done, but there are still numerous stock 'dings' visible in spite of this. But it's certainly a real Jungle carbine, & like all old milsurps it has a value.
I'm not a jungle carbine 'expert' by the way - others may be able to chime in & tell you a lot more about it.......