Interesting I have a 5MD '16 Lithgowwith a H stamp on the Butts wrist and windage rear sight and mag cut off I think it still has the original H barrel, now I may be wrong and have in the past it has no scalloped section on the left rear of the fore wood for a sight plate.
I have heard that WWI Marksman were issued these with the heavier barrel, I will dig it out of the safe as it only sees the light couple of times a year for a drink of BLO/Min turps and an oil up and wipe down and back in the safe it has a pristine 5MD Lithgow 07 and '16 Lithgow Teardrop scabb as well they cost more than the rifle to get together !!!
I may get it out of the safe it resides in and post some pics for the forum to interpret it is nothing special just I was born in W.A and have a connection to the 10th ALH and 25th LH hence the 5MD, it is a right pain in the butt to get to due to the position of the safe.