Chrissa
You've had some good advice here. Make sure all door & windows are locked, as he could get in through them if he can do so without breaking in. Definitely do not let him into your present house. Talk to him at the door if you must but just to tell him you have no income, are living on benefits & cannot pay him. I trust you mean the car is registered at DVLA in your son's name - if it is registered in your name then he could well make an effort to find it. Whatever - keep it well away from the house - not just up the street.
Rossendales - in common with a lot of bailiffs - can be aggressive & belligerent. Do not lose your rag with him, but just politely ask him to leave.
You cannot let the situation continue. You need to come to some arrangement to repay the money over a period of time. It is possible the Council could do this by deduction from your benefit, & there are legal limits to the amount they can deduct. Talk to them about it.
If you want to let the bailiff have the stuff in your old house then do so, but I doubt whether it will make much of a dent in the amount you owe. But I would not let him go into that house without you - or your son? - being present.