Climatronic Intermitent Fault

Hi

I have just bought an '05 Octavia and I'm experiencing a problem with the Climatronic. It works fine from ignition for about 20-30 minutes, then it fails to blow any air into the cabin after gradually tapering off in strength. Although you can hear something trying to blow very loudly no air is coming out. Turing the system off with the centre dial and leaving for a few minutes rectifies the problem, only for it to re appear a few minutes later.

Anyone got any clues how to fix it - I suspect that it maybe to do with the flaps that control the airflow behind the dash, or an associated relay / fuse or motor

Anyone had this issue and managed to resolve it?

Cheers

Dan