Hi,
Here's another Brit. Dumper you may not have seen, like some of the Muir Hill and Motorail dumpers in this thread it dates back to the 1940s.
Made by Marshalls from 1939 to 1945, the 2.1/2 yard machine used the Marshall Tractor single cylinder engine and transmission.
The dumper needed to travel skip first so the forward gears needed to operate in the opposite direction to those of the tractor, Marshalls achieved this by reversing the rotation of the engine. The dumper was also fitted with a differential lock.
Sorry about the poor quality of the pics but their all I have.
Fred