Must be on sale in a physical shop in the UK, likely a newsagents or supermarket.

Easter themed outlets not included (if such a thing exists 😅).

Someone in the UK needs to be able to provide proof (a link will do, ideally to local news source of some repute) - your nan's cousin's daughter's ex's fever dream does not count as proof.

We have until 11.59pm 31 Dec to find such proof.

Good luck and happy hunting 🐣