at this thread!
A few thoughts;
Disabled spaces - should be next to supermarket, big, checked regularly for interlopers who get on the spot fines!
P&T spaces - not necessary imo, but if provided should be wide spaces at the back of the car park, so that they are not 'desirable' for other users. Could be next to a trolley station.
Gangle - you do sound quite anxious, but I think most mums are with their first. Can I make a few suggestions to make things easier?
Don't bother with a change bag in a supermarket - it's just one more thing to carry. Or if you really need it, get a rucksack style one.
Don't bother with an umbrella - keep a roll up cagoule in your bag - if you get a big one then you can wrap the baby up as well.
Try and use a trolley that either has a baby seat, or has a car seat holder - they are SO much easier.
Petrol Stations - either use a pay at the pump, or if you really can't access one, leave the baby in the car. I know to some people this feels wrong, but honestly, for every risk you can think of for leaving them in the car there is a risk to taking them out.
For example; a car might reverse into the car with the baby in. True. But it won't be going fast. A car might reverse into YOU carrying the baby, crossing the forecourt. Baby would be more injured by the fall to the ground, or actually being hit by the car.
Do you see what I mean? Nothing is perfectly safe, and I honestly think it is SAFER to leave the baby in the car (where you can see it) than to try and carry them across the forecourt. And once you have a toddler, or more than one child then there is no question.
Fwiw, I take all 3 of mine to the supermarket, and they just have to behave - ds2 goes in the trolley, dd and ds1 each hold a side of the trolley. It works ok.
Don't think I'm having a go at you - I just don't think you will enjoy your baby as much as you could if you are constantly worrying! And obviously this is a message board, and I don't 'know' you, so am only going on what I've read!