No formation details found.
The Gilks-Grenside Special No.6 at Clapham Junction on 27 September 1969. The tour ran from here to Derby with a trip to the tram museum at Crich. It was formed of three-car Swindon Inter-City set L508, presumably W52099 + W59819 + W52088. Stuart Mackay Collection.
Do you have any images of the set you can add?