Sir John Day was flying helicopters on Active Service long before either of the Pilots of ZD 576 had completed Primary School.
Cazatou
Then, assuming he knows what a flight and cockpit voice recorder are, what motive did he have for telling a committee Tans was a "black box recorder?" The only answer I can think of is to present as factual, information that was not.
Assuming you agree with Day's words and that you know so much about Tans, which would seem to be far more than Racal do as they stated it was not a recorder, then perhaps you'd like to clear up the anomalies being discussed here.