Clicking on startup

[synchro]

When I start the car I get a constant clicking for about 10 seconds from behind the drivers side dashboard. It also
Does it when I hit the recirculation button. I've read of this problem on mark one Meganes but has anyone had this with the mark two?

I think it's definitely a vent flap having problems moving but can't see anything looking up into the dash from the drivers footwell. Any ideas?