This actually fixed it.

The tablet I'd bought fairly recently to use as a map based GPS in Daisy has had a screen glitch that pretty well renders it useless, so being a sort of hopeless loser that will have a go at fixing near anything I thought I'd try something simple.

I decided to try simply removing and replacing the screen's ribbon cable, the one at lower left here, as well as the upper left one which I think may control the touchscreen, then the real surprise came when I started it up again and the picture was lovely and clear.
Of course something bad had to happen as well, as I'd left the TF card in place that I'd put back in to reboot and destroyed it when I clipped the case back together afterwards, bending it, bugger.