Couple of points here:- who signed for the T-34 when it was "issued" by the Hospice? That's the first port of call for the Old Bill (although I'm prepared to bet they won't even bother). If I were you would send the signatory (borrower) an invoice, then take things from there. You do have some sort of Property Control system, I presume?
Next ... there's no way that it sold for that amount at any car-boot sale that I have ever been to. They don't even go for anything like that at Hilditch. £ 12, more like (if that) - especially if (when) stolen.
Unfortunately, those pumps will never be recovered. Thieves are thieves, and there are plenty about. But appealing to their "better nature" will never work (as they won't have one).
Sadly, you need to write them off (the pumps, that is); and probably tighten up your procedures.Having just taken a quick look at the state of play on eBay, I must say I am surprised at the amounts being asked. Some fantastic profit margins there. There are even some junk T-34's on there (clearly indicated as "for parts or not working") that the seller is looking for fifty quid a piece! So sadly, it looks like there is an incentive there for thieving low-life to make easy money. What else is new?