A Blue badge holder can park for 4 hours on a double yellow line as long as it is not causing an obstruction. Some councils have their own rules and shorter times.
We are getting into complicated arguments here.
A 'parking zone' will have rules such as ' Maximum 1 hour, no return within 3 hours' But a double yellow line IS NOT a parking zone . A blue badge holder could park for 4 hours move 6inches and park for another 4 hours as long as it is on a double yellow and NOT in a ' parking zone' .
My wife is disabled and has a blue badge , we can park for 4 hours in all the places I know in Hertfordshire and Cambridgshire, even Addenbrokes hospital which is VERY strict allows 4 hours for a blue badge holder.