Alan- Try DocChris’ reset trick. After no response from my ticket I tried that and it worked!
As Docchris says;
1- TAKE ALL YOUR DISKS OUT.
2- Push a paperclip in the reset hole (beside the power socket).
3- Keeping the reset button depressed, turn on the unit.
4- Hold the reset button depressed for about 30s
In theory you are supposed to see the power light toggle after 30s. I didn’t see that- just saw the unit start booting properly.
After that I would suggest;
5- Keeping the disks out, let the unit boot fully, then shut it down before putting the disks in.
(Just suggesting that to make sure that the unit is definitely finished resetting before you put your disks anywhere near it).