You are right. I have just teleported myself back to 1970 for an urgent editorial meeting with Jeremy Isaacs and this will now be addressed in part 13.
Totally agree that it is the best documentary series ever made. I have the dvd boxed set, but will still watch if a repeat is on tv. And to think that all 24 (?) episodes were broadcast on prime time tv at a time when there were only 3 channels. How times change.