Would it not be possible to do everything relative to the bottom of the page instead..., or if that doesn't work use the center screen "play in full screen" click button that is provided rather than the play button at the bottom... or maybe use a zoom mode? I don't know. Is this really unsurmountable?
In general though, I guess I was suprised when I saw that you are using the physical iplayer webpage to do the selection, rather than just working directly with the flash stream, embedded in a local holder for playing purposes (maybe in the sort of way that get_iplayer does, albeit badly). It seems much of your effort involves keeping up to date with web site changes, and this might avoid that problem, and give you much more flexibility.
All that said, I very much appreciate the work you have put in to this. The latest improvements look very interesting! At the moment this HD issue is the only thing that causes me trouble - but as I am rather fussy about my image quality I end up exiting and using iplayer directly... which annoys me as much as it must have annoyed you when you started developing this

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Anyhow. Thanks again. Just suggestions, and I know the work involved so fully understand if these don't make it to the top of your list. However if there is a quick fix I am sure I am not the only one who would appreciate ...