IDeal standard - cistern removal?

I've seen a post on here that advises to remove the buttons on an Ideal Standard push button flush, to uncover a screw which hold the cistern lid to the mechanism underneath.

I've removed the buttons, but no screw. I can only see the surrounding chrome trim and two rods which the buttons attach to?

Tried prising the trim off with a flat blade screwdriver, but feels as though the trim might snap before it comes off

Any thoughts?