I found this while having a bit of a WILF. I've been in the security industry for the best part of 20 years,and this is the cheapest,most comprehensive bit of personal kit on the market for years.
http://www.pakatak.co.uk/tracker/tracker.htm The applications are widespread and I'm sure you could find a use for at least one of them,Sabrina's stolen foals for instance (sorry to hear about that). I know it costs £150,but a small price to pay I think........... Ree
PS I've no affiliation with the company or product