If BA were approached as to selling G-BOAC in it's enhanced condition to a private purchaser what figure would you assume financially as to it's value.
The main reason they are loaned to the museums, if so BA protects its image rights and ensure that no hard can come to the a/c due to un authorised work.
If one went up in smoke it would reflect badly on the BA brand to the majority of the uneducated people who read a tabloid newspaper.
So for this reason BA would not sell them.
I the longer term 20+years, its likely that BA will give them to museum that have seen to have down a good job and can be trusted, not to take money off some
PR company for marketing stunt and paint them in orange or red!
However BA turned down many tens of millions for a long term loan deal to take G-BOAB out to Dubai, so that sort of says a Concorde can't be bought