Weekend of wiring, and by the end of it I was finally happy. The wiring to the ECU looked terrible, I really hated the run up the bulkhead and across to the ECU and couldn't leave it even if it was correct. Stripped off the heatshrink and de-pinned the plugs and worked backwards until I had a bundle of wires only and rebuilt it. Mounted the ECU tray to get a feel for the wire run and make sure everything lined up.
Still got 2 pieces of heatshrink to place and shrink into place (they are still on the back of the plug) where the wires are held by the tie-wraps to stop it rubbing through
All the wires are now very clearly marked!