Buzzing noise

Hi folks,

Im getting an unusual buzzing noise coming from behind the dash, the location is basicly just below the instrument cluster, theres a little vent which i believe is for the climate control but it seems as if the buzzing is coming from around that area.

Its a 53 Plate Zetec-S TDCI Facelift.

It only happens when i put the key to position II or start the vehicle, so its something going on. I dont want to start ripping things out without knowing what im going to be looking for etc. Its not under warrenty unfortunatly (ford) but does have sales warranty from where i got it (only had it 4 days!) Its going into the garage today for an investigation but i want to have a good idea myself incase the feed me with bullpoop!

Thanks!

James