just to update this thread...i mentioned this to the dr at my last clinic appointment, they could think of no reason for it and simply told me to go to my GP if i was worried! wasn't too happy to be honest (but thats another story)
My blood pressure is normal, heart rate normal.
Yet still I can hear my heart beating in my head all the time...it pounds away at night making it very hard to sleep/relax. This is an annoying symptom I must admit.