No but I am a Pilot at Biggin Hill Airport, I don't claim to be someone I'm not. But the T7 has a set fuel burn rate [SFCs] for different periods of flight which for this flight worked out to be 40T of trip fuel. I assume you know this.
The aircraft going missing had probably 70℅ of it's fuel uptake left - so 5-6hours unburned at time of dissapearance.