The brown leather scabbard appears to be an Australianicon made variety of the P1907 scabbard.
It was officially known as the No.2 Mk.1 and has the double stitched leather (with 2 seams) and the small circular frog stud.
These were made in Australia in the early 1920's and are considered to be quite scarce.
Its perfect match bayonet would be an Australian P1907 made in the 1920's and with the LITHGOW stamp on the ricasso.