I whipped the head off again just to make sure that it had not done any damage. All looks fine. Turned the cam shaft with a spanner to check movement of valves etc, all ok, just the resistance of the springs as you would expect. Stripped out the cam followers to check free rotation of cam shaft, again no problem, shaft turns freely by hand. I marked the cam belt on the first strip down so Im pretty sure it went on the right way. So in other words Im not sure what caused the problem. With the head still off, whats the best way to set up the timing. Kent cam FB32. All my original marks are in place so will use these if I have to and try again at the weekend with fingers crossed.