Yeah, tried new batteries. If I move the LCD ribbon the image changes so I think the ribbon has a damaged connection in it. Probably the line that selects the first half of the LCD.
Also, my GP32 is now so modded (button LED's, spray painted, 64mb ram, battery voltage level mod, CPU core volt mod) that I don't think I could send it back
I'm gonna try playing around with the cable some more but don't expect any results tbh.