PetrolDave I think you are over-exaggerating your size
. The round cap on my Avant is closer to the size of a 5p coin.
The screw also had a bolthead so either use a magnetic screwdriver or a socket to unscrew it and as stated be careful as if you do drop it a lot of the trim will have to come off to find it.
Or as stated in the manual take it to the stealers