I just noticed that although it is otherwise indentical, the transparent case has different mountings to the black one, the support posts and their screw holes are much smaller in the transparent case and it comes with small self tapping screws which aren't even long enough to reach through the Pi board to actually secure it
I drilled out the support pillars using a 2mm drill so the stand offs could be screwed in but you have to be careful as the support pillars are already so much smaller they might split.
I also cut / filed about 1.5 - 2 mm off the stand off threads so they don't have to be screwed in so far. (This may be worth doing even with the black case as the thread bottoms out in the screw holes and they are quite hard to screw in all the way)
One advantage with the transparent case, you don't actually have to drill holes for the LEDs