Litebulbs - yes, what you say makes sense.
I do remember that DH posted something at the time of his dismissal that BA refused to de-roster him and that he decided that it was more important to do union work than turn up for his rostered duties. This posting, which I cannot be bothered to look up but is out there in the public domain, may well come back to bite DH hard. It may cost him both any ET verdict and potential unfair dismissal compensation.
It would not be the first ill-advised posting from the BASSA leadership, LM's comments wrt members leaving on VR being entitled to vote for IA that they could not possibly take part in would be one of these.