The manual is decidedly unhelpful as you and I have both found. I've got some other stuff up on the hoist at the moment (see my Kat post) but when I get a chance I'll stick the Cox up and see if I can get some photos for you that might help.
That other bit in the photo is the cutter engage/adjuster. It goes from a piece at the centre of the crossbar of the cutter lever to the centre of the blade boss.
