Hi Graham my name is Henry. I've read your post and downloaded the post for alphacamm, the problem I'm having is that the code stops running when it gets to a radius, of any size, then I have to reset and run for it to continue only for it to stop on the next bit of code with a radius(or beginning of diameter). Is there a way around this problem. I would appreciate help with this issue as I am about to purchase a complete retrofit kit but I need to know whether this could be resolved. cheers