As BASSA's own QC admitted in court that BA could vary contract terms by issuing three months notice of change, the 1948 redeployment agreement is hardly relevant. BA can use SOSR and if at a later date this was challenged at an employment tribunal all they would have to do is call Mr Hendy as a witness.
This is a red herring and should be dismissed as an option based on BASSA's position, already stated in front of a judge.