Those are all really good resources. I found most of them too. The 2 useful ones for me are the 'instructables' and 'notreble' threads.
The 'notreble' thread shows you how to program a Behringer Foot Controller (similar to the Roland FC300) but not in the same way that the Chewie is setup.
The 'instructables' link shows you how to build a midi controller pedal which offers the same functionality as Sheeran's FC300/Chewie combo. The 'diystompboxes' thread does this too, but attacks it from a different way.
Interestingly I also found you can buy a Sheeran inspired mobius controller. http://www.sonnit.co.uk/
If youre looking to build a *exact* clone, you need a FC300 (programmed to mobius to start/rec loops) which you can then control using a separate bank of pedals (Chewie). This makes building the Chewie easier as you dont have to source/program a midi module and LED logic which is too complex for me to understand. Note - You cant use a behginer as it doesnt have external control inputs. OR...
You could build a unit with all the midi capability built in.
In fact either option is too much of a time/investment waste for me. I dont need it. I can see the practicality for a talented stage performer.
I just wanted to understand the technology behind it. Which I more or less do now. Except for that 1 knob on the pedal below the right display. Is this a level control or what??? I guess we'll never know given this is a bespoke pedal.