I've had this discussion with a collector a number of years ago and kept a copy of the link from Ian's website:

New records discovered at the S.A.F. Lithgow Museum...
The Australianicon machete bayonet was originally intended for the new No.1 Mk III* H.T. sniper rifle! Probably as a tool rather than to bayonet charging Japs with a sniper rifle.
Notes on conversation with Lieut. Pyke, 24th Nov. 1943...
Regarding the inquiry for 3,000 short heavy barrels for sniper rifle conversion. A firm in Melbourne is making the mount to hold the telescope, Lithgow will assemble them to the rifle. The M.G.O. is having Machetes made for use with these rifles, they require pommel and crosspiece fittings assembled to them similar to the operations on our present bayonet. To see if this work can be performed by us, they are forwarding a sample Blade very shortly. We are to then see whether we can assemble the Pommel and modified Crosspiece and finish machine similar to the Bayonet. We will need to supply wooden grips, screws and nuts for securing same to Machete'.

Early machete bayonets were profiled on Bren equipment at Lithgow; bayonet production was at Orange by this stage. The run of Machete bayonets, approved in April 1944 for Airborne troops and re-designated Bayonet 'Parachutist' in 1946, was probably at Orange. Many were destroyed although some sold surplus in the 1960's. A.I.A. had produced a new model as well.

http://www.enfieldcollector.com/archive.html

Hope this helps.