Humax 9200T suddenly has blank 'recordings' list?

Device was working perfectly but suddenly the 'recorded programmes' list was entirely empty. The disk is 60% full according to 'HDD control'.
It has continued to record scheduled recordings but when we attempt playback, although the machine thinks its playing something...(it tells us its a longstanding stored recording, not the recent recording)...the screen is blank. The progress bar is visible.
I have applied 'default settings', switched the device off and re-powered it, but to no avail. It has the latest software installed.
I bought one of the first machines and its been fantastic ...but this might just be the end.....help!