It's been installed for 3 days now.  Didn't notice anything unusual on day 1, but on waking up and heading into the kitchen we clearly noticed a rather loud hum/whining noise coming from the fridge.  It has persisted ever since.  Either something is wrong and it needs fixing or this is the true operating noise and it will be returned.

Shame really as otherwise it is a top-notch fridge, but when I can hear it from the other room, something is not right!