Robin,
I have stumbled across this link:
http://onf-nfb.gc.ca/en/our-collecti...cles&pagenav=1
It appears that the National Film Board produced at least 2 and possibly 4 films on the RAT with the longest run-time listed as 30 min.
I have not explored this far enough to determine how you could obtain a copy of these films.
Colin