I doubt it, though some of the markings might be illegible there are obviously enough clear other wise you would not know it was a disabled parking bay
If you are a disabled badge holder and it was on display and you were not over your time limit yes you can dispute it, but if niether is the case you should be fined and your licence endorsed for parking there in the first place whether or not the markings are there as there is usually a plate on a post as well.
Carlton, you have to be careful they are not sticky-backed, she got into trouble for gumming it to someone's windscreen --- but poked until the wipers will do.