important not to jump to any conclusions re FR24 data which can be erratic as I have witnessed when checking back on my own aircraft.
What I would say looking back on the historical readings is that I have much more confidence in the G-JAMM data than the G-WACG data. G-JAMM's sortie earlier in the day to what likes Silverstone and Wing has painted well and reliably as did the fateful flight taking a similar route although slightly to the east of Silverstone this time. The G-WACG data is much less reliable which is perhaps not surprising considering the relative ages of the two craft involved and the spec of the fitted avionics and there is little low level data on any of G-WACG's recent flights.