The colours have gone funny like specky..

What are the finds?

This issue is usually due to a damaged LCD cable or the contacts on both ends need to be cleaned cable end and logic board ribbon connector side.

If that doesn't work try another LCD cable and as a last resort try replacing the LCD (which is the least chance of it going faulty)

Edit: Badly seated LCD ribbon cable / not plugged in firmly can cause this too. I'll also add in that damaged pins on the logic board where the LCD cable goes in can be at fault too.