I like it!
I like it!
Whoever did that had some skill and knew what they were doing. Nice job!
Form follows function. Many a miltary rifle was turned into a economical sporting gun. Even though I am a restorer, I think that there is nothing wrong with customising if properly done. Of course it is a shame with your old gal, if only because Sparkbrooks are not that common. But it has been professionaly done for somebody, it is a very nice rifle that looks like it would be a good deer gun.
Note that the graceful lines and styling are similar with those of my racing Enfield with an uncut barrel. I have got her ready for deer season, all sighted in, she has a free floating barrel in that forearm and is a tack driver. It shoots better than I can! No problem shooting within 'minute of deer' with it, I hope.
I can just imagine the looks I am going to get at hunt camp when I pull this old girl out with that looooong barrel! Maybe I'll shove some flagging tape in the end just for s**ts and giggles.
Yours could be restored, but personaly, I would enjoy it as is. Maybe put some decent sights on it. The barrel looks to be bobbed a bit so it would be a challenge to restore, it needs more than just wood. Original barrel would be 30-1/2 inches muzzle to boltface measured on a cleaning rod.
If you replace the barrel, sights, forearm, buttstock and added a magazine, nosecap, barrel bands and sling swivels and a clearing rod, you would have a rifle up to original spec.

It would be a fun good project trying to find Sparkbrook marked parts for it, that would be the challenge. Problem is that you would probably spend more on parts than the rifle would be worth restored. I know, I do it every time.
This little puppy is an 1893 Mk.II Lee Metford (before and after) all restored. Basicly, I used the bolt, receiver, trigger group and guard. Took a few years and a few bucks to gather up the parts, but it was worth it.