Boot Strut Bolt and plastic trim removal - help?

Evening.

My right strut bolt has 'dethreaded' itself and come off meaning I have a loose strut and the boot has to be held open by hand.

The bolt and thread looks fine - on putting it back in the hole the nut on the other side has been lost.

I have tried to remove the plastic trim to no avail, however feeling underneath there is a hole that I may be able to squeeze a but through to fix.

To that end does anyone have a guide or link to ow to remove the plasic inner trim to gain access to the bare metal underneath?

Thanks in advance.