It looks like the disk has gone read-only and I'll need some hand-holding

[everthewatcher]

I fixed a HDR-FOX T2 that which was scrolling through the channels on its own...

I'll hazard a guess at what was happening. Both the Vol +/- and the Prog +/- capacitive sense pads on the PCB have a screw between them which relies on the solder resist to stop them shorting together the pads on either side. Spotted this when I pulled the VFD filter off and put fibre washers on them.