Hi Klaus, thanks for your reply.
I had read this several times before posting my question, but I had completely missed the "altvideourl" part, I could not see the wood for the trees !!!
Am I right in thinking that you cannot have another hotspot on top of the video in HTML5 "Multiple Simultaneous Audio or Video Streams" ? as I have 2 "png" hotspots to mask the sky area of the video. These do not work on the iPod, but they do on my computer.
Jeff