Thanks for that.. I could have sworn that it wasn't active.
Anyway, it was active, I tried it but got a "Raid 5 Expansion Failed".
Nevermind, there's only about 600GB on it (after it deleted all 3TB of my data doing a Raid 1 to Raid 5 migration, exactly as the instructions said to) so i just copied it all to my 2TB linkstation, reset the 419P+ and started again.
2 processes in a row this thing has messed up lol, but also my fault that i didn't back up, nothing important lost admittedly lol.
Thanks for your post