It's nothing to do with the WT act, I couldn't give a fig about that.
The fact does remain though that it was an internal NATS production, produced by and for NATS, ŠNATS and to the best of my knowledge was never intended to be released outside of NATS. The fact also that it is not the full article but a part of it also suggests it has been removed surreptitiously.
I hope NATS are able to track who had access to it and find out who leaked because NATS has a lot of training material such as this (though not always as dramatic!) containing real r/t and radar recordings of incidents and I don't want to think that I or my colleagues are in store for more stuff escaping into the public domain.
The flight deckers round here might not be too impressed if more escapes either because much of it doesn't reflect particularly well...