I didn't actually observe the HST transit when it happened. I was alternating between binoculars and the live view on the camera, so that if it did miss Jupiter, I could see by how far. It was 8 min before sunrise so there was no warning of the HST coming with the naked eye. I recorded 2 min prior and 2 min after the predicted time and by the time I stopped the movie I thought I had missed it entirely. My secondary objective for the morning was to photograph the Moon at 1 day before New but clouds were obscuring.
Dejected, and packing everything up and getting back into the car, I resignedly reviewed the video on the camera and saw, just like you see in the youtube video, the quick flash of the HST. I was delighted and pretty excited, and could freeze the video on the frame where the HST was on the disc. Even now watching the video the sense of anticipation is pretty cool! (I've added this description to the first post)
I've reprocessed the image based on more frames to increase background brightness, which brings out Europa and Io. I think I prefer the first darker image, but this one is more akin to what it would have looked like through the telescope 8 minutes before sunrise. I've added the image to the original post.
Thanks everyone. Here's screenshots from the CalSky and Stellarium predictions 1 hour prior to the event. I think they both did pretty well considering the tolerances involved! The ground track screenshot was recorded after I got home after the event. The little house symbol is where I was (which was on the predicted centreline an hour before the event) and the centreline predicted an hour later. To acheive a central disc crossing(!) I would have had to move to the NW.