Its probably the water pump you were hearing, not the radiator fans. I have an AU and I'm so used to it now I dont notice it...
From the little I know, the BA has a direct drive water pump, which means you wont hear the lag of the water pump fan starting up/or shutting down.
I noticed the lack of water pump noise when I test drove a BA a few months back, it was almost spooky !!
In fact, when I first took delivery of my AU back in August 2000, my water pump(s) failed to start up due to a faulty thermostat. This, along with loose head nuts caused by head-gasket to blow at 96km !
Must have been a Friday afternoon car ..