Classic coercive control.
He had isolated you from friends and family.
You are living rurally (more control over you).
You don't work so are financially dependant on him.
Emotional blackmail - threatening suicide to get his own way.
He knows you have £11k savings. This is a threat to him as you could use it to leave. So he takes it from you under the guise of needing a £16k car. Now you're broke and can't leave him.
You are now completely under his control and he can treat you however he wants.
Please speak to women's aid and read up about controlling relationships.
The car issue, if you must buy the car (are you scared of what he will do if you suggest a cheaper car?), then yes YOU can be the OWNER and he can be the registered keeper for insurance purposes. Make sure you pay for it and it is YOUR name on the ownership papers.
You'll never get those savings back, he is ensuring you can never leave him. However, please try, for your children's sake as well as your own.
Good luck