Danny,

Sorry to hear of your neighbor's misfortune. In this part of the world, where guns are still permitted to be owned by ordinary citizens, the burglar has a good chance of being ventilated. If I recall, in the UK only criminals have guns. If that's the case, an alarm system, with an outdoors sign may be of some benefit, and could possibly act as a deterrent. Just some food for thought.

Good luck,

Gary