If you're talking about the one where Zippy, Bungle and George are swearing their heads off, then I don't know if it was released on video but a clip was shown on that Victor Lewis-Smith programme about five years ago but I can't remember the name of the prog... Sorry... Perhaps it will come to me... hang on, It was called "-----------TV..."
It was called TV Offal. The Rainbow clips in question were done as a christmas tape given to members of staff at Thames TV. I believe one of the clips can be found at a site called 625, I will post the URL when I've tracked it down...
Hello mate
If you're talking about the one where the double entendre's are flowing more so then my Saturday night's cider habit, you wanna go to the following link and, once loaded, you can view the whole thing online. And believe me, it's a cracker !!
http://rainbow.arch.scriptmania.com/rainbow_tv_episode.html
I think it was one of the specials done for comic relief and was shown quite late at night. I think the Whitehouse lot complained. I seem to remember that they did a couple of the comic relief sketches