Poundland were criticised as far back as 2012 for multi pack selling.
https://www.chemistanddruggist.co.uk/news/rps-change-law-stop-retailers-offering-paracetamol-multipacks
A limit of two boxes per person has been in force for years as a half hearted attempt so stop suicides (one box is enough to kill you if taken all at once anyway)
Why are supermarkets allowing this? Why not have them at the pharmacy counter and sell two boxes at a time manually?
The panic buyers are raiding the supermarkets (I saw a photo on Facebook of a bloke with two trolley loads of disposable nappies) leaving the small corner shops alone.
Our local Facebook group mentioned the small corner shops still having items available.