Riva Super America (and similar models) Replacing owner cabin bed lights

Hi all!

I have a question. In our ownercabin in our Riva Coral 45 from 1989 (basically a combination of the Riva Superamerica 45 and 50 - same layout and guest/owner cabin) we have 2 bed lichts behind plexiglass in the ‘bed boards’. I want to change these lights but can’t find a way to access the armature. I tried losening the ‘vent board’ on top of it but - besides the airco vent being attached to this so it has limited space to lift it up - the lights are mounted in a box fixed to the side board.

It seems access needs to be dismounting the side board, but does not seem to ‘click’ off, I can’t find any screws or see panel mounting when looking in from the top when lifting the top vent board. I don’t want to force it by pulling it to hard. Any ideas?