DMR - Designated Marksmans Rifle.
If you look closely at the drawings they show that the scope mount is actually attached to the RHS of the upper body ( upper receiver for some ) and does not rely on a dust cover solution as that had been tried and failed. There is a re inforce that goes into the removed carry handle slot.
It was never intended to be a sniper rifle, just a more accurate L1A1 with an optical sight. Some of the mods pioneered in this then became commercially available in the "Target Shooters Package" that used to be put together by the now deceased Des Batcheldor when he was at SAF Lithgow. Back in the 80's you could pay $125.00 more for your SLR and Des wound do a trigger job, tighten the headspace, smooth the action rails and bolt carrier, and generally tighten up a few more bits to get the rifles shooting a little better. And they did shoot better. He was a lovely guy and a craftsman in every sense of the word.
What should be done with the drawings - maybe give them to the SAF Museum at Lithgow ?