That was a "fun" recording by the crew and was never shown on British TV until Channel 4 aired it as part of a programme that immitated "
Sparky's Magic Piano" series which was broadcast late in the evening.
The clip from Rainbow was uncovered purely by accident when programme makers were thinking of compiling DVDs of past childrens' programmes to help us to waste more money we can't afford.
The Sun newspaper got hold of this "episode" a few years ago (not long after it was discovered in the archives) and printed the entire transcript.
It's a bit like Captain Pugwash. No, they didn't really have those amusing names, The Sun newspaper made those up. If you want to know what the REAL names were...
http://en.wikipedia.org/wiki/Captain_Pugwash
if (empty($mug->content)) {$mug=new coffee();} else {consume($mug->content,'more');}
I wanted to change the world but God wouldn't give me the source code.