Watched this series back in 1973/1974, and taped various episodes onto audio cassette from my 14" black and white portable Hitachi Hitachi TU-75A television set, via the 3.5mm mini jack plug outlet, normally used for listening with an earpiece.....
Kept them for years....I still might have a couple of them knocking about.....
Superb series, with 'Larry' the cherry on top as narrator.
A series everybody should watch at least once in their life.
I picked this up for a fiver about 3 years ago - the original DVD boxset before they cropped it to widescreen and "remastered" it. One of the best fivers I ever spent. A genuine piece of TV history.