It seems to work miracles, a friend of mine suggested KIWI black liquid shoe polish, I tried it, it was £2.60 for a tube with a foam applicator and to my amazement it works miracles!!!!, I have put the car through the car wash and it hasn't faded one little bit, I reckon its the same stuff as the plastic revivers that you buy from the likes of Halfords and in any case, its so cheap that if it does fade, just put some more on, but it seems pretty durable to me
here it is
https://www.sainsburys.co.uk/shop/gb...ne--black-75ml