Thanks for the replies guys, I'm very much hoping (fellow optimist) its plugs or coils but if it's more serious is it worth fixing head liner damage or would it be best trying to source a doner engine? Bare in mind I just had timing belt done 5k ago plus temp sensors.
Will get news tomorrow once it's been examined. One thing mechanic did say is that he appeared to be imparting blame a little on the fact that rad pipe in question appears to have swollen prior to contact with belt pulley, mentioned engine may have had some contamination in water of some form that caused pipe to balloon. I have a photo I took whilst waiting for pickup down into engine bay if anyone's interested showing the contact between pipe and pulley.
Either way it doesn't get round the fact I probably should have not driven it one inch once I'd noticed high temps
