Jon,
as you are going to do this I thought this might help.

The ali is basically 2mm thick, my tin snips weren't up to cutting it. A nibbler would allow you to drill one hole & cut that oblong box shape, I don't possess one so opted for the 2 hole solution plus I wasn't sure how cutting the box across the bend in the cover would impact it's strength.

Fleabay sell nibblers from under £20. It could be very usefull for the oil filler where the gap from the cover to the box is so small.

The ali of the cover is backed with insulation. I was worried the disc I was cutting out would fall into the cavity but the foam holds it if you are carefull, though I was also able to stop cutting and leave a small part of the disc connected to be safe.
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One of the discs I cut out.
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JohnV6
2022 CX Plus Four
2025 MG ZS EV aka Trigger