The animations were created mainly due to the featured bands not being available to play in the studio and not having a promo video.
This from a reviewer on caio about the DVD that was released to mark the programme's 30th anniversary.
They have also left out some of the wonderful �videos� that show produced. In the days before proper video release to accompany a song and where there was no live footage of the artist available the Old Grey Whistle Test used to add their own graphics to the track, this could include old film footage set to the music or strange experts of avant-garde cartoon films. Many time the choices of these graphics was inspired and it seemed like the tracks were specifically written to accompany them. Some of the most memorable included the surreal cartoon to Frank Zappa�s �City of Tiny Lights�, the 30�s dancing girls footage accompanying Led Zeppelin�s �Immigrant Song� and �Tubular Bells� accompanying a black and white film showing a downhill chase on skis. I�m sure I didn�t make these up!
http://dvd.ciao.co.uk/Old_Grey_Whistle_Test_DV D__Review_5278574