I fitted these last week & feel your pain. It’s the worst bit of bike spannering I’ve ever done. In the end I threw the instructions away as they are clearly wrong. They suggested fitting the front guard securing thingy behind the fork?! The text doesnt even match the drawings in the instructions. Complete joke. Anyway I was going to post some photos of how I managed it but never got round to it, away now with work so will have to wait unfortunately.
The key I found was the little black plastic bits that the wire supports sit in. I cut the very tops off with a Stanley blade. This way you can slide the wires through, get the perfect fit and tighten the little grub screws. Then you can cut the excess wire that’s poking through do they are flush. Once I did this it was dead easy.
Ps be careful not to ping one of those screws across your garage…1 whole hour searching on my knees with a torch to find that little ba***rd!