There was a shock from fans on Sunday in the UK; when Cineworld updated their website for the Spider-Man No Way Home movie release date to be December 15. This lead fans to be in disbelief about the information and asking for confirmation, as maybe this is a placeholder still.
Now, the official Film Distribution Association (FDA) for UK and Ireland website that documents all past, present and Future releases and Box Office information has also moved the release date to December 15.
The film was originally set for a December 17 release date on cinema sites and the FDA. The date has so far only changed on FDA and Cineworld. Cineworld and FDA have been contacted, yet to hear back from them.
Update: After contacting Film Distribution Association for further confirmation. December 15 is the new release date for UK and Ireland. Officially confirmed via email.