Cool.all from http://www.roadtransport.com/blogs/big-lorry-blog
Looks like the back wheels also steer
This and the last photo in this gallery are both 4 wheels under the cab.
It seems similar to an F.A.R. http://justacarguy.blogspot.com/2009/01/three-wheeled-tractor-trailer-rig.html but definitly not similar to the Scammell or the Tempo, so it seems there might have been another 3 wheel delivery that I haven't learned about yet.