i know it might seem like a stupid question but how do i get them off

ive taken the 2 10mm screws at the front off, ive taken off the little plastic bit off thats attatched to the wing and i undid half a turn on the triangle kind of shaped bit at the back so its not attatched.

but now the only thing stopping it is the triangley shaped holder is on the engingebay side of the front panel, how do i get that off then thats my problem sorted