£20 box off Amazon (GPS tracker/vehicle locator/auto-fuel-cut-off/etc. box - basically GPS + relays connected to GSM).
One giffgaff SIM card on minimum payment (£5/month) so they don't shut it off.
Wire into existing doorbell.
Done.
Sure, not a "commercial" product, but are you honestly telling me that it costs thousands of dollars to package that up in a neat box that just plugs in?
Biting the hand that feeds IT
