When I say "display panel" I meant the VFD's glass. This is the big bit of glass with pins at the bottom of it. DO NOT do it with the power on, as there's 60v on this part (and on the display PSU).

You should be able to just get your fingers on both sides of the top edge and gently pull the display towards the bottom of the case. It won't move much, but you're trying to get the bottom edge of the glass around 1.5mm from the metal lip on the bottom of the front of the case.

Hugo