Early BSA Sporter Safety ...

I've had this BSA sporter (very similar to No.3 pattern) rebarreled with a new SMLE barrel, and am in the process restocking it. While I haven't decided with sights to use - either a set of NECG express or a Metford rear ladder set, I do have a question. Can the cocking piece be changed for the earlier one with the safety lever? The current is the half cock, and while I understand that it was original to the rifle, I would prefer something safer and easier to use while hunting.
https://www.milsurps.com/images/impo...aa64a590-1.jpg
https://www.milsurps.com/images/impo...48e893d9-1.jpg
https://www.milsurps.com/images/impo...3a6e4249-1.jpg

No. The bolt body on a MLE bolt is longer at the rear to accommodate the larger cocking piece with safety lever. PM me if you want a MLE bolt.

Is there any evidence this is a factory sporter rather than a rifle assembled from parts, or put together by one of the smaller gunmakers, either in NZ or the UK?

The wood doesn't look like a BSA sporter IRRC and the magazine appears to be one of the Parker Hale "Made in Japan" models, perhaps tidied up a bit and modified to clear the cutoff?

If the bolt is numbered to the rifle it is better left as-is IMHO. It MAY be a factory job after all, or the reworked remains of one. The LEC actions were commonly used for that purpose before WWI.

you could always go for the tang safety like the early BSA sporting rifles

I never use the safety when hunting. I find it easier to leave the bolt handle up

My guess is that the rifle was initially made as a sporter by BSA, later clumsily re-barreled with an SMLE barrel. There are no acceptance marks, nor a crown stamp on the receiver. I suspect that the stock in the first photos is original, as the forestock has been carved out rather coarsely to allow for the rear sight to seat. The magazine is an aftermarket conversion, probably Parker Hale, which I've replaced with an SMLE version. Here's what I've done to date:

https://www.milsurps.com/images/impo...8b71a502-1.jpg
https://www.milsurps.com/images/impo...8c075840-1.jpg