i've removed all of the securing screws i can find, including the ones behind the two circular blanking plates. its almost off but its snagging on both upper corners where the blanking plates are. i can just about see some rubber gasket type things that might be holding it on. i don't want to pull too hard and crease / tear the plastic

(just fyi, i need to take it off to get the numberplate mount off. took the two front screws out, then realised its also secured from behind.)
i know ther'll be unsightly holes where the numberplate mount was, but i'll smooth them when i respray my bumper and wing mirrors.
thanks for any help.