....you could always cover it with a Saudi themed wallpaper. Remember the paste goes on the non patterned side.
Just leave it man, go with a two tone effect. Or put some coving up to cover it if you haven't already got some. Then get the cans oot !
It's always best policy to leave about a third of paint in the tin you're using, add the new tin to it and give it a good stir. It's not unusual for paint colours to be slightly different even if the batch numbers, colours etc are the same. If you're going to roll before cutting in, do one wall at a time then cut in as the you'll still have a " wet line " as the rolled paint will not have dried.
