A little OT but...
My wife recently tried to fill up at a new (to us) station. She had trouble getting the diesel nozzle into the 'nanny' filler restrictor. She gave up and told me the nozzle must be the wrong size. Which was bad news since this station is the closest (and cheapest) diesel station to her mother's house.

So a couple of days later I checked it out and found that the nozzle was the right size but it had been dropped on the ground so many times that the alumium tip was dented in at the very top as you put the nozzle straight into an X5 filler tube. This dent caused the 'nanny' filler restrictor to not allow the nozzle to open the metal plate that blocks smaller nozzles. All I had to do was turn the nozzle to 90 degrees and it went in easily. Then I could turn it back vertical to actually fill the tank.

FWIW the metal plate is released by two small black plastic 'triggers' at the very top and bottom of the filler tube. These 'triggers' must be activated simultaneously. An undamaged 'normal' diesel filler nozzle touches both of these 'triggers' at the same time as it goes in and releases the plate. A small (i.e. gas) nozzle can only touch one or the other but not both.

Funf Dreisig