well ive had one of the end caps off and if it weren't broke before it bloody is now.

It aint ment to come apart, take the 4 screws out and pull the plastic end cap off to find one edge is glued in with some sort of resin with 3 metal contacts set into it.
Thats now broken but is the only way into the unit so bba would have to do the same, further in on the end of the shaft are little filaments that run on a track. they seem too short and worn and have scratched into the track, they also sit at an angle that would make the return stroke far from smooth and make them dig in. What a load of crap.
Several pieces of swarf fell out of the unit, to course to be ware so must have been from the manufacturing process. Magneti Morelli, somebody tell the italians to leave electrics alone. Thanks for the replies though Kevin, always helps to have a second opinion.
Still wouldnt mind another company to Quote on it. Any recommendations?