Lump tickover & smoking out of the exhaust... help?

[James H]

My well be the head gasket but the car has only done 66,000 miles & has sat around for the last year when I drove it home it was fine started her up a few times to have her ticking over But other than that it hasn't been driven (I have been working on her a fair bit removing & cleaning things but nothing major), any other tell tell signs I should look out for if the head gasket has gone?