Just to conclude on rebooting it reverted back to previous behaviour. Contacted support and likely to be fault so returning it. Thanks again for help though - as nearly got there!
Hmm, well I’m still not sure that you have any problem with hardware and it would be a waste of time to replace it. I think that current firmware might have an issue with saving settings (including those that you get from calibration). I’ve been working on a UI that gives you access to some OWL internals and is meant to be a wavetable editor and noticed this issue a few days ago. And another user mentioned the same problem recently.
You could try to downgrade firmware to the one that had old flash storage and try saving settings there. It would probably survive a reboot as it used to work. Then just use that firmware version until an update that resolves this problem is released.