Sometimes I wonder if my view of the UK is disproportionately skewed by what I read on Mumsnet.
As someone not from the UK and one who doesn't live there, I find it mind boggling when people suggest they can't take their kids out of school to attend the wedding of a close family member because the school won't allow it, or they are worried about asking permission, or they'll have to pay a fine. It's such an alien concept to me.
But then I read this thread, any my mind is blown. What the fuck is wrong with some people? Parent and child spaces are a courtesy, not a legal right. Like others have indicated, there is no governance of them, no badge requirement, etc.
The OP had a need that not everyone has. A space was available that met the OPs need, at no cost to anyone else. Yet, so many here, and the batshit busybody in the car park, pile on because it says the space must lay in waiting ready to accept an as yet unseen and unknown parent with a child in tow.
As he got older, my Dad, whilst not eligible for a blue badge, found getting in and out if the car a lot easier with the extra space a P&C space provided. He benefitted from being closer to the door and not having to negotiate a trolley through a car park. Not once in about 5 years of doing that here was he ever challenged. Some people would even offer to help him when they saw he'd parked there. Do you know why? Because not everyone's an asshole.
Stop being assholes to people who need a bit of extra support every now and then. A sign doesn't make it okay to not use common sense. And a sign certainly doesn't make it okay to abandon empathy.