Still no video.
The player loads and shows an image, the video bar shows background video loading progress and even clicking to certain parts of the video shows different image clips. Just no video. So I've just given up.
I'll happily work with you to figure out the issue, even if it means giving you a link to download some videos in the meantime.
Firefox has an "advanced" setting (about:config only) to prevent media automatically playing which was preventing playback - even with the video player's buttons. about:config | media.autoplay.enabled | true -> breaks the player.
However there's another anti-tracking option that prevents embedded videos even being displayed - Preferences | Privacy & Security | Tracking Protection | click [Change Block List...] -> 'Basic' works, 'Strict' doesn't .