After a few experiments and discussions, I finally settled on this design for tidying up cable mess. Two models are provided to allow you use standard printer filament (either 1.75mm or 3mm - both models are provided) to tie everything together.
Once you've printed however many parts you need for the length of tidy you want to create, take a length of filament (or string, elastic, electrical wire ... anything really that will fit neatly and can be tied off) and begin stringing on to the filament alternately cable chain part, then separator. Once you've cable all your chain parts used up, take a second piece of filament and begin to string through the cable parts on your chain already and add a separator between each.
Now you have every thing on the filament (and this is where you'll have to adapt if you're not using printer filament), cut the filament at one end and use a lighter (or other heating device you have to hand) to deform the end of the filament. With the filament slightly molten, use a pair of pliers of knife or spatula to push on the end of the filament to spread it slightly. Do this with both filament trails at one end, then pull through the filament at the other end of the chain to get the chain straight and the filament taut. Repeat the process to melt and deform this end. You're now done and should have a complete chain. You're now ready to string your cables through.