Whoop, whoop, front end noise

[Seagullsport]

Driving home this evening, intermittent. 'Whoop, whoop' noise from front end. No loss of power at all, no missing. Drives perfectly. The fact that it comes and goes is odd. Remained very noticeable at steady 50mph, accelerate and it went, then will return randomly. Can just about 'feel' it in the steering but not too pronounced at all. Not sure what else to say but a bit disconcerting. Because of performance it does not sound like engine. Could be wrong etc. Basically where should I start looking ?


Thank in anticipation, John