I had exactly the same happen to me. When applying to a new employer I told him about the incident; He was fine about it.
My police check came back clear in the end!
Just to add, if you have no movement sensors any where, if someone should gain entry i.e an upstairs window then they can move freely throughout your house as long as they want and only set off an alarm as they leave arms full of your valubles 30 secs down the road