Simple little things but someone might find them useful.

I was putting up some 10mm thick LED lighting panels in my workshop store and ended up having to surface mount them as the gaps between the joists were 5mm too narrow to slide the panel inside. Oh why didn't the original 18th century builders use proper metric measurements? :-)

In my case the LED driver is just sitting on the top of the panel but if you wanted to surface mount to a flat surface some simple spacers would do the trick.

You'll need two each of the left & right corners and, optionally, two centre supports for a 1200mmx300mm panel.