Time to give this great topic a bump!
I have been meaning to share these pictures for ages:
First, a stick one of my children found in Cirencester Park made me think of this:
Here is the stick (I think it was Ivy when alive)...
...and with a clear plastic ball it looks quite like the PM version!
Here is the second one, the 'real life' version first, a piece of equipment dumped on a farm in Wishanger:
and here is the PM version...it's a bowser, to carry water, or slurry (liquid fertilizer derived from manure):
I looked up the word bowser and discovered it comes from the inventor, Sylvanus Freelove Bowser.