Basically, my house is haunted (it's about 500 years old) and the "occupiers" are not friendly, there have been a few tantrums but nothing I can't handle.
I have laid down the ground rules but they seem to be ignoring them when I'm not around.

My Girlfriend is a little nervous in the house as it stands, she doesn't know about the interlopers I'm a little worried that they might do something when I'm not there and she is that might scare her even more or hurt her.

Something was following her the other night, it smashed her make up mirror and then blew out the light on the stairs when she went down to put the mirror in the bin.

I didn't appreciate that and dealt with it but the question I have is should I keep decieving her about goings on in the house or should I expunge (I love that word).

I really don't want to tell her, she has a nervous disposition.
I also, however don't want to clear the house because of a couple of bad apples...