We want to install smoke detectors in our timber stables. The alarm must sound away from the stables eg a bell inside and outside our house.

There are radio-interlinked units manufactured by Ei Electronics that are battery operated and suitable to connect stables with a house. Just install alarms in the house as well as the stables and all alarms will go off at the same time. However, keep in mind that the smoke alarms in the stables will sound as well if you have a fire in the house or if you are testing the alarms. You might have to modify the sounder in the smoke alarms placed in the stables if this is an issue (careful, this might affect warranty and function)