Single air vent not blowing air

[kps]

Hello all.

I am really struggling with this one. 

I noticed the driver's side air vent on the outside of the dash does not blow air whilst all the other air vents do. 

Have felt around inside the dash through removing the little bit of trim at the end of the dash. Can feel air blowing in there. 

Somewhere between the heater matrix/blower and the vent, the duct has become disconnected. 

I have no idea how to get into this part of the dash. 

Any ideas?

Cheers. 

Fiesta Mk7, 2010