I used to watch this too at junior school in Petersfield Hampshire around 1975. The odd thing is that from time to time I still think about it (I am now 40) The big question running through out the length of the series (no idea how many episodes 6??)was the identity of the person riding the motorcycle !'I've ask friends in the past about this series and they have no idea what I'm talking about and think its some kind of weird dream I've had. I've never understood to this day the educational benefit of this but thought at the time it was great but slightly scary. I seem to remember that there used to be a break of some sort in the middle of each episode. No idea why. Would love to see it again. Got hold of a short clip via the BBC cult website.