OK - those following on FB will know the extent of the damage. For those who don't here's the prognosis.
FLUFFY IS FUCKED!!!
The exhaust valve head has snapped off and gone walk about destroying the head, piston, liner and turbo. I have a spare engine which I'm going to put back in with my old T25 (did 200 ponies with that) on standard cam and probably limiting to 16psi to get me going again. With the old engine out, I'll strip it down and have a good look about for possible porblems and set about repairing what needs to be repaired. First thing first I'll get the Turbo off to CR Turbo's for a quote on work needed doing.
Anyway here's the gallery
Valve head snapped off and hey presto - fooked everything. The collet is still nicely holding onto the rest of the valve above LOL. I will never surrender.

The breather system was showing +ve pressure LOL.

On the plus side, this gives you an idea of the thickness of the piston top.

On 1st inspection, I thought I had got away with destroying the turbo.
However...........................

Not so much. Sorry about the crappy photo.
So there we are, more work to do, I have a spare head which needs a skim and is currently @ 72.75mm which I might be able to use, I'll have to see what the advice is on that, the turbo is in the hands of CR and the engine will have to wait for me to get around to stripping down.