Looks like the garage the dealer used damaged the small fan, making the large one compensate? Reason I say they damaged it is it's totally seized & they only fitted a new air con pump last Saturday, which is right by the small fan coincidently...
Anyway, I've called the dealer & told him I'll not be taking it back to them & I want it fixed locally, they can pay my mechanic £240 or deal with VW, or I'll return the car. Only had it 3 weeks so it's still under warrenty.