Well, I know it's frustrating but look....
... it was a life raft from your aircraft.
Are you sure it wasn't somebody who jumped over the fence to grab ? I'd be suprised if a pilot would steal a life raft to use. We're all so paranoid about safety a dodgy second hand life raft wouldn't inspire me with confidence. Sort of like flying an aircraft that's been "hot wired"
"Nah mate, nah worries, I've got both magnetos on have a crack"
On the other hand in the last couple of years my car has been stolen and my house burgaled twice, plus my 50cc scooter was thrown down the stairs of my local car park. All in all around £6000 of theft and damage, so in some ways, you could be happy that it was only £800 and not MUCH worse.