There's a short bit in one of
Ian Skennerton's works that tells of receiver replacements being done at Lithgow. Much the same as John R's story over on the ZF thread, except IIRC these were only done at the factory.
In trying to get my head around the need for replacing a receiver, I suppose (and this is all supposition) at a time when Great
Britain had just lost many thousands of weapons at Normandy and was under threat of invasion...
Australia was gearing up and needing more weapons than we could produce.
Production figures put new rifles at only about ten per day in 1939-1940. Perhaps it was shortages of good aged stock blanks that controlled new rifle production... They would have only been cutting enough to replace the slow useage through the thirties. I don't know how long they had to dry for, but by the fiscal year from 1941 to 1942 rifle production got to around 375 per day.
Shortages of stocks would make repairing/ replacing receivers on otherwise functional old weapons very attractive. Every one that came from repair was one more than they could assemble new, without being a strain on wood supply.
I don't know what your thoughts are, but it is a very interesting rifle indeed.
As an afterthought, does it have an assembly number on the rear top of the receiver?