The roundels were fitted in very much the same way as the old ones: simply stapled to the back of the wall panels with a staple gun.
This picture is during the process of removing the old roundels. I was hoping to reuse most of the lighting diffusers for the new roundels, but the staple holes (and splits) prevent a proper vacuum from forming, and also enlarge as the plastic softens.
Some of the roundels are actually pretty rough close up - they seem somewhat organic, but then organic is fashionable in TARDISes these days, so I can live with it. They really don't have the detail you get on a fibreglass one either.
The new roundels emphasize the difference in backlighting between the wall and corner panels.
I don't think I've put up any other pictures with the main lights turned off. The downward lights remain on in the evening under computer control, or whenever I just need less light and heat. It's easier to see the roundels when they're not back-lit. There were a few occasions during the show where the roundels were not backlit.