Ordered grade B handset from CEX got the wrong PSU

You are being unreasonable.
Charger is a gift.
Samsung A53 don't come with charger. (edited)

I've had this plenty of times with them, unfortunately with a Grade B you are not guaranteed the original charger.

I have managed to get it swapped for a better charger at my local store but it really depends on how your local store is, some are not so nice.

I thought in the past grade b was all original accessories, just box not included? I maybe wrong. Anyway if you sell a phone to them now with A condition. They look at it with some blue light or magnifying glass to see scratches so they can grade it lower and give you less. Imagine if you used that when buying stuff from them that's graded A.

Essential accessories mean the bare minimum to get you going. SIM Eject tool, USB cable and plug (if one was supplied with the phone originally - If it was supplied with just a USB cable in the box then a plug isn’t essential)

Since the requirement is bare minimum. The accessories don’t have to be official. Any charger that meets UK safety standards and will do at least 4.5W charging would be considered acceptable.

If you want an official fast charger then most CeX stores have this in stock for £10. There’s a range of compatible options on Amazon too.

The latest fast charging isn't essential to use of that product. A 6W power supply like that one is going to be more than enough to fully charge it overnight. (edited)