Like everything it only matters if it's enforced, and that the perception nationwide is that it is both illegal and being enforced. This requires education and consistent application, not just random signs with different rules.
Everyone knows that you'll get done if you park on double yellows, but most people will treat EV parking bays as no different from parking in Parent & Child bays, etc.
People still drive in motorway lanes with red X's above, even though there was a campaign of teaching people that it was now criminalised, etc. I fear there is a long way to go on widespread respect for EV parking bays.