The issue is with the license plate illumination, rather than the trunk (I'm sure that'll be an issue at some point).
The left light cluster is dim and flickers (the right-hand side is fine).
I tried undoing the smaller lens screws but (without potentially damaging anything) the lens did not lift off so that I could see the LEDs themselves. Removing the larger outer screws just allowed the light unit to wobble inside the bumper, with no clear way of extracting the unit for replacement.
Is this a CSP-only replacement or can someone tell me how to get the old unit out, procure a replacement (maybe for just the LEDs themselves) and reinstall? These sorts of things should be DIY jobs, in my opinion.