Hi Phil,
I have had several small claim court experiences and this is what could happen.Firstly the judge will probably just look at the established facts of the case.Forget your 30 day warranty or whatever you give,new MOT,forget the LTD company defence,that is a clerical error,it's not the high court.The car was returned for repair within 30 days.Subsequently,the customer called to reject the car on the grounds it was unfit for purpose.The judge may want to know why you did not collect the car and inspect it.The customer will probably say he could not return it because it was too dangerous.The customer will say because you rejected his claim,he was forced to get an independent inspection.He may bring his mechanic as a witness.
While the reality is that your customer has probably been put off the car and has been unreasonable,the judge may differ in his opinion.While I have won small claims prosecuting banks,architects and others,I have tried to defend some rediculous car sales small claim cases ,even offered proven evidence showing the claimant has lied.I have never won one yet.The bottom line is judges do not like car dealers and you are taking a chance by defending the case.