I think thats unfair to suggest disabled drivers are any worse at parking that able body people. Yes they may take a little longer to get in and out of a space but personally ive not seen any really bad ones.
Have seen plenty of bad parking in disabled bays – have seen plenty in all the other bays as well.
Being a poor driver does not come down to if some is disabled or not – it’s just that some people just can’t be bothered to drive properly or learn how to do it better. Think a lot of people think they are much better at driving than they actually are as well.
Would be quite interesting for people to have to retake their test every 10 years or so!