I have recently upgraded my broken QC2s and the cost was about £120 I think. I received QC15s with the Apple in line cable so I was very happy. I just took the old ones into my nearest Bose store (Cheshire Oaks) and they swapped them with no difficult questions.

My QC2s were really old and yes they did break in the usual place but I think the fact that Bose will 'upgrade' them after 6+ years is very reasonable.