Found this rattling round the door pocket where it's been stashed for an unknown number of years. The quality of the previous work on this van is... variable... so it's entirely possible he was just too lazy to find a bin for it.
I have Google image searched but that thought it was a PAS pipe for a Traaaaaaanzit so of little use. For scale it's roughly 4 inches in size (stop sniggering at the back).