2 I have your registrations.
If the BAeA decides to take action, (and I hope they do)
As a fellow aviator, you could contact the pilots, calmly explain
in restrained language what you saw, acknowledge that we can all make mistakes, and urge them to be more careful in future - for the flight safety reasons you mention and to avoid the risk of someone complaining about/reporting them.
I'm sorry you've been unwell. Perhaps it would be better to wait until you've fully recovered and then decide, on calm reflection, whether it still seems worth bothering?
Even if you still think it is, what you say to them then may be more measured. The extravagant adjectives and adverbs you've used here are unlikely to be conducive to productive discussion.