This from the DCMS.

Entertainment facilities are defined by the Bill as facilities for enabling persons to take part in music making, dancing or similar entertainment, for the purpose of being entertained.

An antique piano in a pub that was only provided for decorative effect would not give rise to the need for a licence.

And a licence would not be required if the pub operator did not allow the public to play it.

A licence would only be required if it was used to entertain people at the premises or by people on the premises to entertain themselves.