Here's a link to the six development aircraft, with pix of all of them.
CONCORDE SST : PROTOTYPE FLEET
Several had different paint schemes throughout their history, so that may not be definitive. But there are variations that can narrow down which might be in your painting: long or short tailcone, and small window or large greenhouse cockpit visor.
Three of the six are British G registrations, and three have French F-numbers. Three have "...01" production numbers. As ChristiaanJ says, none would be registered "1-GEE" - but that might have been something added for a specific test flight or for some other reason unrelated to registration. They
were repainted occasionally (including one painted in BA livery on one side and AF livery on the other, for a time.)