Sounds like once she realised she could manipulate you it was a short step to bullying you.
Threatening to lose you your job? Where does she think the money to pay for the car, house, etc will come from then?
When she applied for leave to stay in uk was it because of you ,your marriage?
If that is over tell her you will need to inform the immigration that she is now breaking the conditions of her permission to stay.
Not saying you will do it - but call her bluff, bullies dont like being exposed or stood up to.

Mezzie,

thanks for the post. Yes you are right. I have been standing up to the bullying and life is quite a battle - just simpe things she can be obstructive about. Will probably just need to keep quiet and calm as it will probably get me down.

Threaten to reprt me to the police if I spoke to her son - but he seemed more than happy to ask for my help with the computer - no problems at all.

Not sure the immigration thing is possible though now that she has got her visa to remain.

That seems a dead end

Thanks for the support advice

Sea