Hi - thanks so much for your reply.
I was aware of the mobile utilities and in fact I had a note on my phone with all the commands, just not the only one I was hoping for yesterday : restore to "userdefaults" because it was added in the latest firmware. It was restore to factory that I was hoping to avoid.
With this link I was able to upgrade fw, and then use the command to restore to user defaults. All good now. So thank you.