Commercial Breaks & Beats

Hello all, I'm desperate to track this down but have littel to go on. It sounds quite folky, and like it is played on a euphonium (if that is how you spell it I has a gentle lilt and could be a dance. It has been used on the trail for lits of porgrammes from channel 4 to bbc - have not heard it on ITV.
I know some-one out there will have a clue. Thanks
Pugdog