UPDATE:
I've added a frame with a mounting hole so that this system could be attached to a wall. I've not printed one but I imagine it should work.

UPDATE:
I've redesigned the slots that the dividers fit into, they now run across the bottom of the tray as well. Previously I had issues with small items slipping between compartments, this alteration resolves this. I've made the slots deeper and tweaked the divider design. All the parts should now work as I originally intended.

UPDATE:
So I've printed the final four frame sections in order to finish this section of my build off and I've noticed that the sections don't fit very tightly together. They don't fall apart but they aren't a snug fit like they were previously.
I've recently made some mods to my extruder drive to try to improve the resolution and I think the improved tolerance is the problem.
To try to improve the situation I have added some tiny "bumps" to the female mortise areas (they are only 0.25mm high so I don't think they show on the preview image). I haven't tried printing it yet and I don't plan on it any time soon so I would be interested to find out whether it has helped if anyone tries the design out.

Linking storage system that I designed to hold all my 3D printer spares.
Frames simply slot together
Trays can be separated into 1,2 or 3 compartments as required.
To get to the point in the photo has taken weeks-this thing takes forever to print but it has helped organise all the nuts, bolts and other parts I have laying around so it has been worth it in the long run and should I need more storage I can just slide another module in.