I just noticed that you are in the UK, so perhaps things are different over there. In the US, you could be arrested. I have seen it happen to several friends and acquaintances.

A friend of mine had her 21 year old daughter and 18 year old autistic son living with her. The daughter got her brother drunk and started provoking him. He broke the tv and she called the cops, claiming he was threatening to kill her. She was also drunk and is a pathological liar. The cops don't know that. The brother was arrested. It was considered assault somehow even though he had not touched his sister. She told the cops she had lied, but it was too late.

My friend spent 10k to get the charge dropped to a level that didn't require jail time. He has to register as a domestic violence offender and will have that misdemeanor on his record forever-- over his sister's lie!

I think it would be a good idea to contact a domestic violence organization in your area to see what thoughts they have about your situation. What if her parents file a report against you? What if she does?