Whitley Engine Data Plate Question

Hi

Could anyone help me, I have a very nice Whitley Throttle Quadrant that I want to display, however you will see in the photos, that there is a small ‘frame’ for sliding some information in, rather like the compass bias card holders you see on control panels.

looking in the Whitley pilots notes, though a poor picture, there does look to be an arrow, on Fig 2 pointing towards this area of the Quadrant in which it says it is the ‘Engine Data Plate’

Now, can anyone give me a lead onto what this plate is or ideally looks like ? am I to presume it is like the standard Merlin Engine Data Plates that we see in brass ?

though this particular ‘frame’ looks too small to hold one of those brass plates ?

any clues greatly received .

Jules[ATTACH=CONFIG]232831[/ATTACH][ATTACH=CONFIG]232832[/ATTACH]