Unfortunately, this is a limitation of the scroll event on iOS. It does not given intermediate results - like it's debounced - only firing the scroll event when scrolling has stopped. This is a well-documented shortcoming of iOS. As Apple puts it [0], "One-finger panning doesn’t generate any events until the user stops panning—an onscroll event is generated when the page stops moving". There is no workaround at the moment.
wiresurfer, don't understand why you were down voted into oblivion, but now I can't reply to you. Anyway, massive thanks for that, really helpful starting point
Till the time its seen by the right pair of eyes :)
Will try and see if I can fork a version and add the "inferred " touchend hack to it. Have a good day.