Sorry can’t help except to suggest doing some gentle probing with panel removal tools, on a warm day when plastic is not too brittle. Other than that, visit a good audio installation company that does work on up market vehicles and is more careful. (.....probably)
Great location to do a spot of DIY though.
PS There is a post on this forum of an MP stripped out to insert insulation.
Search “Noise insulation”.
I have just checked the pictures - none showing the panels you are interested in so not much help.