Sorry to dig this up, but I didn't want to start a new topic for something relatively paltry

Bought a set of Airtags at Apple through the e-store at £99 at a rate of 6 Avios per pound spent. Today I get an email that 284 are on the way for a purchase amount of £47.20. Not sure where they get this amount from. Even when VAT is deducted that should be £82.50 or 495 Avios.
Anyone got an idea how this amount could have come to be?

OTOH, I bought something for my nephew on another retailer's website at a rate of 5/£1, spent £60 and got the full 300 Avios, so including VAT which usually is deducted.