GL, the last person you should blame is AG.
He is a lawyer not a bus specialist. If any, it was the poor choice of Arriva, and, by the way, don't let Mercedes know that you think that their buses were 'headaches'. They may sue you for damages! LOL
A bad workman quarrels with his tools but when convenient we seem to side with the operator rather than teach him a better way to use the tools. Does it not strike you kind of odd that the bendy-buses started catching fire and in rapid succession just before Arriva left this impossible island of ours?
As to who bought them - that's a State secret, however, who cares?
As to the amount they sold for - it is not in the public' interest to know. So there!