No1 MkIII... I think?

[Bruce_in_Oz]

The "model" marking is interesting, as well.

My old eyes see what looks like a "equals" sign after the "lll".

That would suggest that this is one of the Mk lll* rifles that were re-graded to proper Mk lll spec. by putting all the "fruit" back on and striking out the "*". This apparently happened in the 1920's.

Any other ideas out there?