Thanks
@Punkawallah; I'm trying to deal with Weinmann brakes as well. I've spent much of the day off and on trying to get them to work as I wanted, but I'm doing this as a learning exercise as we have several bikes with side and centre pull brakes so I want to get proficient in their maintenance.
I see the point on the Third Hand and I'll probably order one for this type of brake. As I didn't have one today I had to improvise, so I borrowed a clamp from the wood workshop and clamped the brakes to the wheels before I fastened the cable bolt. I still had to wind up the tensioning bolt a lot on the rear brake but I think that's also because of the long cable and continuous outside. I think I can safely trim off another five centimetres when I resume maintenance next week.
I like the Weinmann brakes though: they look smarter than V's and seem to work fairly well.