Phoned Naim Customer Support. They think there was a problem with the update - that it wasn’t installed as it should have been. I explained that I had done a factory reset but to no avail. The person I spoke with said that there’s nothing further that can be done and that they’ll send me a replacement through my dealer. It’s frustrating given that this will be the third unit.
Also, I’m not sure why the unit required me to update it as the update is almost 6 months old - I would have thought they would be done at the factory before distribution (I only got the unit on Saturday). Oh well, hopefuly it will be resolved soon.