Sometimes they play this piece of music while walking through properties. It doesnt have words and sounds quite 'holiday-ish' and very chilled - sorry cant think of anyother word to describe it - have been chasing it for a few years now!
Just email the BBC and they will tell you! You can contact the contact programme makers directly through their website, and they will probably send you a list of the music used in the programme with timings on- it would be good if you could refer to a specific programme and exact time it was playing.
That should do the trick. If it doesn't, you could try 'His Majesty King Raam' by Lemon Jelly, which may or may not be the answer, but it is used a lot as incidental music on those (and similar) programmes.