I got a reply from Digital UK. They suggested a reset and retune but apart from that not a lot other than contact Humax (they aren't technical regarding PVRs). They did confirm there were no faults at Hannington.
As an aside did you know there is a mortuary at the Hannington/Cottington Hill aerial site. I have no idea why but noticed it there on a previous work visit (smart metering).
I have also had a couple of tours inside the transmitter hall. One quite a few years ago and most of the equipment was still valve based and was cooled by using the latent heat of evaporation of boiling water to steam.
The second visit was just a couple of years ago. Most of the equipment now is about a 10th of the size and using modern electronics.
Simon