Series 3 How would you go about finding a Series 3 Landy? Q631 EGV

My parents used to own a ex-MoD Series 3 that somehow got taken/lost by a (ex)friend. This was about 20 odd years ago now in Essex. I have the number plate. I’ve checked it and it’s SORN and no MOT (shockingly). However, it had a V5C issued in late 2015 which gives me a glimmer of hope that it’s still out there. The reg is Q631 EGV if that helps anyone? I can try and get some pictures somewhere but no idea where they might be.
TIA
*Edit* just found out about a V888 form, worth a try