Hi CambridgeAce,
Welcome to the fold,and nice to have another UK Ace on-board. Assuming that it is the standard silver /grey colour, courtesy of Tad, when he did his fairing, he had the paint analysed as follows: Kawasaki Grey Ninja ZX12R Code KAW 7E.
I can verify that this is absolute spot on as I used this code to paint my fairing and it is identical to the OE Skyteam colour.
You should be able to get a touch up pen or pot from Halfords or any motor paint specialist made up to order. Good luck!