Thanks for the reply,

I previously updated the PF firmware in early February this year, to whichever version was current at the time. I have found a FactorLib file from around the same time which should have at least some of the presets I lost, but now FactorLib won't send it to the pedal. It recognises the file type, opens it and lets me edit it, but the filename starts with (unknown) instead of (PF) and when I click Save to Pedal I get the error message "Cannot send unknown presets to PF pedal".

Also if this helps, the pedal itself is now filled with what look like demo presets: Storyteller, Teenage Wasteland, Trance Octaves etc.