Mystery access panel; Help needed

Can the collective intellegence of the forum help me.
I’m now getting to the end of the task of identifying and cateloguing items of aircraft recovered from an airfield dump, the majority are Horsa and Hamilcar parts but this panel doesn’t fit the bill for these two aircraft types, its aluminium and not plywood for a start.
[ATTACH]199430[/ATTACH]
Its badly crumpled and like all the other parts it has been subjected to burning. Two things stand out about it, however.
1) Is the strap holding the Dzus fastener a method used by all or just some manufacturers? (Desperate attempt to narrow the field)
[ATTACH]199431[/ATTACH]
Rather than attaching to another panel it is fixed to a alloy ring with small holes around its rim.
2) Are these for screws to fix it to a wooden structure, or lace holes to fix it to fabric?

A mystified Aeronut