The Type 9 gearbox reversing switch location leaves <1cm to the tunnel side. With hindsight I should have organised the loom/plug for it before the gearbox was installed:
The standard GBS loom comes with 2x spade connectors which are completely unsuitable. I took apart a couple of bullet connectors (Red Bullet Sockets from Maplin seem to be right), carefully bent the end at 90 degrees and covered with shrink tubing to make the appropriate connectors. Its still a fiddle to get these in place: