Ok here goes.
Firstly I share your frustration at misuse of spaces in the example you gave.
However, I think it's a massive misconception that P&C spaces exist for the simple purpose of providing more space.
It's also a misconception that they are close to the shop because people potentially have mobility issues when travelling with small children.
We know most parents (but of course not all) don't have mobility issues that require them to be close to the front door. That's what blue badge spaces are for.
The common conclusion many people therefore come to is that wide P&C spaces should be at the back of the car park and not taking up useful space near the door that anyone with other needs could use. If this were the most IMPORTANT reason for P&C spaces I would agree.
In my mind, the most important reason for having P&C spaces at the shop door is that young children should be kept safe because cannot be seen in car parks. They cannot be seen when you are reversing, they cannot be seen between cars, they could run out at anytime. Anyone pushing a heavy trolley at 5pm in the dark with two small children could tell you how dangerous it can be.
Any death or accident in a car park that could have been avoided by keeping children close to the shop and away from cars is one too many.
The extra space is a convenience since most parents do need to open doors wider, but it's not the primary reason for P&C design in my mind. I use plenty of P&C spaces which are normal sized.
Therefore if it's just extra space you need (and since you haven't mentioned any mobility issues), I don't think you should be using a P&C space which could be used by a parent with toddlers who we would all want to be kept out of the way of cars.
I would suggest you park further back in the car park and away from other vehicles to give yourself the space you need.
I haven't intended to offend anyone on here but I'm sure I probably have! Good luck with your pregnancy.