Thanks for the comments guys,
Ned, yes when is the opportune time? My lawyer thinks it may be better to wait for the tribunal hearing first - if it comes to that. Of course, she is liable for damages but anyone would prefer not to go there.
Cutting water off, getting my sparkie to fiddle with the meter box, turning the gas off - don't worry they all go through my head but I shall restrain myself and act like a rational being. We shall leave emotion aside and go to the tribunal with no ammunition for her.
The update is that she has returned early from holidays and asked for an extention to allow more time. We refused indicating that there are storage sheds and temporary accommodation options freely available to her and we have a mortgage to repay and a contract of sale to settle. She then plays the emotional card. Oh, I've been in Melbourne helping my elderly mum into a home and I have an autistic child. My refunded $34k deposit was all returned to my ex husband in USA. Well we heard she also spent some time in Fiji!
She hasn't indicated at all whether she will be moving out or not so we shall see on Tuesday morning. I am well prepared for an immediate lodgement for an urgent tribunal hearing with all documentation in chronological order which includes:
Contract of sale to purchaser
All email correspondence
Residential lease
Notice to vacate
Proof of mortgage + request for our loan on the property to be repaid by 31 Dec + default notice with threat to us of legal action to recover loan if not repaid upon due date of settlement - 24th Jan.
Prepare for the worst but hope for the best.
The amount of inconvenience that one person can create for everyone involved because of their contempt for legally binding agreements.