BUSH BTU 160 DTR freeview + recorder?

I also have a recording problem with this model.
I maxed the hard disc recording to 0% available for recording (while I was away on holiday).
I have now deleted most of the recorded programs BUT BUT it says that 0% is still available.
In the "set up" details of s/n etc. that 88% of the hard disc is now available.
BUT BUT it fails to allow any recordings.
In "Messages" it tells me that it was unable to record due to 0% disc space.
So it appears JAMMED at the max used disc space.
So it there any FACTORY re-set???
Or Software Up-Dates available.
OR can I just replace the Hard Disc? Or would I need a programs first installed on any new hard disc???
Does anyone have the phone number for BUSH tech. help??
Or a manual with such help??
I am Roger from Romford Essex England.