As I examined the PCBs, I realissed the other had 5 power inputs and one ground, the other again one power feed and 5 outputs. I could make just one board that works for both sides. This is exactly what I ended up doing. I traced the phototransistor side with KiCAD and soon I had some real life PCBs in hand. The only difference in them is what's on the boards, so the side is decided at the point of assembly.

Much to my surprise absolutely nothing went wrong with this one. The PCBs fit perfectly mechanically and they also worked electrically as expected.

I had also toyed around with the support bracket and it has gone through several iterations, with the shape now enabling printing without supports and the material used in the final version was Nylon. I considered PA-CF but after hammering various test pieces, the PA alone was most likely enough.

So, Doctor Who is finally going to be put back together!