Loss of colour and flickering screen

Got my son an IPad 2 air for xmas, it was reconditioned but company does have a good rep and it comes with a year warranty so we can send it back however would like to see if we can fix the issue.

worked fine xmas morning for about 20 minutes full colour, then the screen started to flicker, we turned it off and on but still the same after 20 minutes…… the colour goes from green to purple ( i.e. message icon is now a light purple )

we have currently put it in greyscale mode and this has stopped the flicker, as soon as we revert back after 20 mins same problem,

any advice would be grateful

thanks