Does anyone else remember this and on which program it was done? It may well have been Channel 4's Me and My Micro in about 1985.

Ah. This person says it was '4 Computer Buffs': http://www.tvcream.co.uk/?p=2347 Found it. Here's a video of how you had to make the 'receiver' for this: http://video.google.com/videoplay?docid=89458723914479030 and here's an interview where there's the software being transmitted at the same time: http://www.youtube.com/watch?v=ULGDTtGZcN0