Trolling a little hard there Jockster! DOJ for ST will be BMI DOJ, for many reasons, both legal and practical.
ST in BA is discretionary - it is not contractual and can be withdrawn at any time by the company. Everytime you use the ST you confirm that you are aware of this. BA can do what they like with ST including giving new joiners more or less of it. In reality, precedent and the dinosaur that is the BA ST computer system will ensure that all BMI pilots will have ST based on DOJ to BMI.