WW2 Aircraft Part ID

While on holiday last week in Egypt I picked up a piece of aluminium plate in the El Alamein area which appears almost certainly to have come from an aircraft. It is an oval plate broken roughly in half so the original dimensions would have been approx 52mm high by 110mm long and 1.5mm thick. It has three small rivet holes running vertically and three flat rivets running horizontally on the R/H side (I assume this would have been repeated on the L/H side).

A factory part number is clearly stamped in the lower middle portion and reads 28507/100. Other numbers and letters are stamped above it but appear to be different in type.

Any ideas as to what it may have come from? Will try and upload an image if it will help.