Yes Bronte - OP wasnt clear - but it was actually -
This from post #11 - I cannot reclaim room till 28 day notice has lapsed
Post #1 - causing approximately 800 euro in damage
And Post 4 - The deposit will only cover half the damage
That make me think its a rent a room situation.
Tenants are entitled to reasonable notice but from what I gather - she ran off of her own accord - I would be inclined to tell her - you are not getting your deposit back, do as you wish (re small claims court, PRTB etc) but also not chase the outstanding balance - get the work done, clean up the room, advertise again and get a new lodger, chalk the whole thing up to experience. If she continues to get nasty and hound the OP only then would I involve the authorities, but it would be for threatening behaviour, not damages etc.