I'm trying to find a tv series starring peter butterworth

In the late nineteen-fifties, there was a series on TV with Peter Butterworth playing Peter Potts, who taught aircraft pilots - I remember him talking about altimeters, wind speed indicators etc. - and solved mysteries. There were several adventures, each having three or four episodes. The only title I can remember is 'Potts and the Night Whistlers', where the criminals identified each other by whistling a short tune. I can find no trace of it; does anyone remember it?