OK It's a 1DsmkII, it had a shutter replaced, within a couple of weeks after the repair it started putting a dark line along the bottom, if high shutter speeds are used I get the clipped top left corner and light and dark banding mostly towards the bottom but also across the middle to a lesser degree. The guy that did the repair started off by saying he does not think it's the new shutter (he fitted) maybe it is maybe it isn't. It did not do this before he had it, but I could sense a tone of 'not my fault".
I had hoped the problem would be recognised here, if you have had this effect you would instantly recognise it and realise it is not a lens hood, cloud or any other suggestions put forward so far. I suspect when whatever is happening happens it would be the same on any modern camera lens combination.
I think it is the shutter, I just hoped I would get a reply saying "Yup it happened to me, it was X". Now you all have the information you are sure you need, the answer is ?
Kevin.