Count you've yet to justify leapfrogging an ex bmi pilot who has an earlier DOJ bmi than you but a later DOJ BA.
How many pilots have left bmi to join BA at significant personal cost?
You cant compare Bmed/ bmi with bmi/ BA simply because it's not fair for a bmi pilot with a doj Pre 1989 taking an A380 command.
When you can justify this on this forum I may believe you can justify it in court.
If BA give you seniority on DOJ would they not also have to give you the comensurate payscale. Can you have number 100 on the list on less basic pay than number 101? I reckon this is what BA will think and will do everything to avoid it by finding an alternative solution.
Peculiarly by a strange quirk of fate the advantages to me of DOJ seniority v bottom of the MSL outweigh the disadvantages but I support what is fair.