I am fortunate i have had a blue badge since 1979 so i can park on double yellows or residents only spaces plus all day on any 30 minute parking. I try to park properly but sometimes there is nowhere to park in a spot but if its all by phone, i will be parked on double yellows outside the car park entrance.
The hospital became difficult with barriers and phones to operate it but it all broke down 2 years ago and still not working, the barriers stay up but they take a picture of the cars. You still pay by phone but my registration is marked exempt by the hospital.