Just about any rifle is restorable with enough time and money thrown at it.
Usually with a long Lee, if it has a shortened barrel, it is not feasible as the barrel would need to be replaced. Not really practical unless the rifle has some great historical or sentimental value.
In your case, to restore back to military specs, it would need a replacement barre, a replacement wood set and a magazine and bolt dust cover. You would basically be starting out with the action and replacing everything else.
Then the mechanical aspect needs to be addressed.
I note that at sometime, the rifle was condemned by the Ordinance Dept, as denoted by the double reveresd R on the barrel's nocks form. Often called the 'twin sisters', this was usually the end of the line for a service rifle. The marking has a cancellation mark through it. The rifle was subsequently proofed at the London Proof House sometime pre-1956 for sale through the British gun trade.
An interesting old deer gun that was somebodies pet project long ago, but nothing of great value in my opinion. It is what it is, enjoy it as a sporter.
Value? It is worth only what a good shooting deer gun might be. Zero collector interest.
