So after buying a shit load of sockets I found the right one!! Took the rest back...

I've taken the head off and I'm concerned about the marks on the pistons
Previous owner said the head had a skim, too much I'm thinking.
I'm gonna be changing these anyway for HC ones so will it be ok??
I've ordered a set of callipers and will measure the thickness, whats an unskimmed head?

Cylinders 1&4 were spotless but 2&3 were oily, any ideas what is going on here?
Looks like the engine was fired up very briefly when out of the car. Maybe the timing was off which resulted in the contact marks.....

The last pic shows the chambers cleaned with a light rub.

One last thing, are the head nut and bolts reusable? I watched wheeler dealers (sorry!) and mr china put the head back on with the used ones