Conversion of FD class louvred vans to FDF class started in 1982, however, there were at least six other FD class vans converted to this standard which were never reclassified from FD. Known numbers of this group are 13416, 13468, 13757, 14156, 14259, 14331. The body design was virtually identical to the earlier FDP class poison van conversions.

I am not sure of the significance of the final letter F in FDF. It could be that these vans were intended for fertiliser traffic. Their career was cut short by the creation of "Total West" and the end of wagonload traffic.