Managers? Are you so sure? By all means, upload the recordings you have. Please. Prove me wrong that it may well have been BASSA officials posing as BA managers making the calls.
After all, if you really think it through, BA have all to lose and nothing to gain by making such calls. Who would gain from such calls at such an early stage in procedings?
Answer that, my friend, and then we can move on, becuase BA cannot gain from such an early polling or as you may frame it, "intimidation" of staff. It does not make sense.
Over to you.