I don't have a Quad but I can imagine loosing any thing worth £1200 must be gutting, I know what I am about to suggest will not help you, but it may or may not help somebody else,
I was wondering if something like this may be worth fitting, they say they have a 80 foot range which would make searching a field a little faster, and you know you wont walk past it an miss it by a few feet, I also looked at some newer bluetooth ones, but the range and the battery life seemed a lot less than these old school ones, and for £25.00 for 6 you can stick them to everything.
http://www.amazon.co.uk/Set-Wireless...s=keys+locator
Good luck, I hope yours turns up,
Mark