MACK said:Might be worth a go, but unfortunately if its a intermittent fault they may check out fine but still be the cause of your issue.
Exactly why I hate intermittent faults!
It's been up and down all winter, I did spend last week driving all around farmland with the roof down and the interior was full of dust when I got home, maybe that got into the mechanism and is causing it to stick, I'll give it a clean and grease. It opened and closed completely normally just now, hopefully that's a sign of things to come!