PA38,
That is exactly what I suggested during the discussion, but was told that was not the way we do things! I got the impression that the instructor felt that I was criticising the flight crews performance, despite my assurances to the opposite, along with a slight disbelief that a member of cabin crew could possibly question the SOP's. That's why I have been slightly reluctant to bring it up again. However, I shall now take Cpt_Schmerzfrei's advice and seek out the relevant person to speak to.
Thanks to both of you for your replies. It is much appreciated!
Jsl