Check out BBC iPlayer for:
Madness on Wheels: Rallying's Craziest Years
Programme covering group B up to the dark days of it being banned with a kind of 'how did they get away with that' commentary.
Fantastic footage from the early 80's and interviews with some of the top people at the time - well worth a watch. Not sure how long it will be available on the iPlayer, it was broadcast Tuesday evening.