Please follow the advice to inform the County Court that she is no longer living at your address, the date she left and that you don't know where she lives now. It's then their job to find her. I'm not a lawyer, but I don't think they can take anything of yours in settlement of her debt. Another GN member may know.Might be worth getting some advice from a high street lawyer who offers half an hour free.
So sorry that you no longer see your grandson, but you have to stay clear of getting involved in her new relationship. You've had one very bad experience of her assaulting you and you most certainly don't want another.
Sending a virtual hug and 
Hysteroscopy using spinal block/epidural
