Big Finish who are responsible for a vast amount of Doctor Who audio fiction. The plot sees the Doctor taking Nyssa back to 1963 so she can witness Beatlemania. However something's gone wrong with time and the Doctor is puzzled to find that the Beatles are a little known group and the biggest group on the planet are a Beatle-like band called The Common Men.
The plot sees the Common Men following the path set out by the Beatles, and this is an enjoyable if offbeat story for the Time Lord. The story plays around with known Beatle myths, for instance a twist is put on the Paul McCartney is dead and was replaced by a lookalike, rumours that went around in the late 60's.
Oh, and the Beatles sort of turn up at the end.
The audio play is available from Big Finish in both download and CD.