"Does anyone know how many safety cases have been carried out by BAE or are being carried out by them ?"
Could be a "How long is a piece of string? kind of question.
They will have one for each aircraft that they are Design Organisation. (Plus a 1/4 share in Typhoon)
But they will (or should!!!) also have a safety case for pieces of equipment that they produce. ie if they are responsible for providing missile x, targetting pod y, bomb z etc etc, then they should have a safety case that will allow the integrator (whoever that may be) to "inherit" the risks and mitigate them where required.
And I assume that you are only thinking about aircraft for the moment. But the need for a safety case covers all major military equipment. So, ships, submarines, vehicles, UAVs, artillery etc etc produced by BAES, should all have a safety case.
sw