Head Up Display image 'rolling'

[atregent]

I'm hoping this is not a major issue, but I'm also kind of fearing the worst

A couple of nights ago I started and drove off, and the HUD image started rolling slowly up (like in the old days when the TV needed a bit of a whack to stabilise the image)

Occasionally it'll shift to the left and half the numbers a cut off, and a couple of times there's just been static.

It's like there's something come loose somewhere (although I doubt it'll be that simple a fix)

I think the battery is on it's last legs (I think it's still the original one from 2010, I've only had it for about a year now), so not sure if that might be causing issues with the video signal stability

Any advice or reassurances would be much appreciated!