eggy2010:I spoke to my cousin earlier which is where i got that act from he runs a game store and knows of that act. Does that apply to private sales or is it just business's?
The law applies to business and private sales differently. As a private seller, your responsibility is just not to be dishonest or to try to deceive. A business seller would be required to make sure that the car is safe and suitable for ordinary use.
All cars are unsafe in an accident if they are driven into a tree at 60mph. If this one is safe at other times, then there is nothing particularly to worry about. It may be just that the mechanic at the garage is trying to scare the buyer as they sometimes do to talk up the price if a job.
Any serious faults in the chassis can usually be seen by inspection - which the buyer did - or by there being a wobble noticeable during a test drive.
In your shoes I would be willing to talk to the buyer but I wouldn't do anything more unless a summons or a solicitor's letter arrived. If you wanted to refund and then resell the car, that would be your decision but it is not something that you need to do. If the buyer wanted you to pay the garage bill and keep the car, then, my feeling, is that you would be being cheated by the mechanic involved and/or the buyer.