Pornpants,
I have no source just that the wording in the email 'has decided not to accept a role within the new BA operating company' sounds similar to when our manager Joy Horden went after Willie Walsh took over. They never said she was pushed but we all knew that she was and they described it in a similar way then.
Of course he may well just hate the job and want to go. He has by all accounts had a horrid year.
I obviously don't know or have any inside information.