Rumour has it that G-BOAB has very little left of the interior as much of it was removed to re-assemble G-BBDG at Brooklands.
IIRC the a/c also did not receive the post Paris fuel tank modifications and thus along with G-BOAA was used as a spares source for the last couple of years of commercial operation as it was no longer certified to fly.
The engines are also long gone and the fwd baggage hold is said to be full of old copies of the BA inflight magazine as ballast.
I never understood why it wasn't placed on that huge roundabout at the entrance to T5 as there is plenty of space, but obviously the powers that be didn't want general flying public to be reminded that they were taking a step backwards by seeing the "old" Supersonic jet when they were flying on a modern subsonic jet.