These are incredibly hard to find items. Seemingly when these water tanks were processed out, the folks that bought them binned the filters and pumps. Either that, or the military took them off for future use.
I found a company that will cast new ones, but I need original examples as a basis. To make a new pattern from scratch would cost a small fortune.
I'm looking at replicating a couple of 'lookalike' filters. If anyone else wants to try this, the attached drawing from the Metafilter instruction manual may be of use.
Regarding the hand pumps, the attached photo shows a different style (semi rotary). Maybe a different tank manufacturer?
Owen.