Yes, there is a particular gentleman who is paid to perform in CCR in the afternoons, engaged via a specialist agency which I think led to a somewhat gnomic post elsewhere in FT. I saw him there yesterday (Monday). He is classically trained and he is apparently well known in that particular music circuit. You can't hear the music much past the high tables, and it's fairly indistinct in the dining booths and board room. Past the bar and on the Terrace you won't hear anything at all. Since it acts as a cordon sanitaire for those lovely marching mobile telephonists I have nothing against this! He also does play tunes relevant to the flights taking off 90 minutes hence (so material from La La Land before the LAX departures). However this is probably more @
Tobias-UK territory than me. And as KARFA points out there is some background in the CCR dining thread.
Only very occasionally does a guest use the piano in my experience, though a member of the RPO was having a whirl on the pseudo ivories last week, to impress his travelling companion.