This is what the department for culture, media and sport website says:

"Carol singers going from door to door, or just deciding to sing in a particular place, or even turning up unannounced in a pub and singing, would not require a licence, just as drinkers in a public house who suddenly decided to start singing carols would not be licensable.

"However, if a business in a shopping mall, for example, arranges for a group of singers to sing carols this will be the same as their arranging any performance of live music and a premises licence or temporary event notice would be required."

The above is not what the words of the Licensing Act 2003 say.