Cancel recording on HDR 2000T

How in earth do you do it? I started recording Digging For Britain directly from the programme guide, only to then realise that it was a repeat. Pressing the record button again brings up a message sating something like 'Cannot modify the end point of this recording'. Going into the list of recordings is of no use either, as every effort to cancel results in 'Function not available'. The Opt + button has all related functions greyed out. As far as I can tell, apart from pulling the plug out, there is no way to stop it. All I can do is let it finish recording then delete it. Surely Humax couldn't have missed this during testing.