they are saying that when they bought the car and did HPI checks on it that everything is all clear so "LEGALLY" they are not at fault.
Sorry to hear about this. What a nightmare.
If your dealer doesn't sort this out straight away then here are a few ideas.
Bad mouth them to everyone you know.
Contact your local paper.
Contact trading standards.
Go and sit in reception at the dealers and let everyone that comes in know what has happened.
They need to sort this out and quick. Outrageous.