Ok.. I've set it to 12 hours (720 mins) it seemed to take...though the live screen shows 1 hour.

I went into the mfs via tivoweb and looked at:

Directory listing of /Recording/LiveCache

This lists:

Name Type Id Date Time Size
3209880 tyDb 3209880 01/05/07 13:13 488

So I clicked on the name and it returned:

RecordingBehavior 3209880/12 {
DiskBehavior = 12
PresentationBehavior = 8
ProgramGuideBehavior = 6
TunerBehavior = 8
IndexUsedBy = 3209880/10

So it looks like it's set to 12 hours (Disk Behaviour).. maybe..
The on screen timeline might be displaying incorrectly?

I'll leave it going for a day or so then see what it's doing.

Something I've noticed is the skip keys don't appear to skip to the beginning of the live cache.. Is there a certain key combination to do this, rather than having to sit and wait for 12 hours (hopefully) to rewind?

Cheers,
ZollyMonsta