Re the video: It's quite obviously a film taken well after the event probably with dubbed sound. There is a ruddy great hole in the cockpit roof - made by the long departed firemen.
The JAA accuracy standards for Mode S is +/- 125' but what is the actual accuracy of the tx units installed? To put any real credence on Google plot with interpolated data collected from a spotters SBS1 unit doesn't sit well with me.
Kegworth scenario / engine failure / stretched glide / stall all seem like plausible options.