Originally Posted by EssexDave

Ok just got back from the shop.The guy doesn't know what's wrong with it.

What he's done is;

He did a compression test. There is some compression, but not enough for it to run.
He thinks it may be a sticky valve, which he thinks he can cure by using a hammer and "gently tapping" it.

He said, if this doesn't sort it, chances are it will be a piston.