I just got back from my first face-to-face appointment with a respiratory nurse. After 4 months of is-it-isn't-it I'm now a fully paid-up member of the club. Go me!
Typically she saw me on a good day, too early for the evening chest tightness to kick in, but at least she gave me time to talk, was sympathetic and believed me. Rather than trying to wean myself OFF the Qvar, I've had my dose increased for a couple of weeks before reviewing. Fingers crossed that this is the answer.