OK, when I took the cam-belt cover off there was a bit of slack between the cam pullies and the timing marks did not line up. I carried on stripping the head off although was tempted to sort the timing out and fire it up to see what was what but decided as I had it half stripped anyway I may as well carry on.
So this is what I saw
I have turned the cam with a socket and all the valves seem to open and close smoothly and seem to seal OK. But is there any way to tell without removing them from the head? I thought of putting some petrol on them to see if it seeps away.
The dings in the pistons are very shallow and don't look any deeper than the pre-formed ones for the exhaust valves.