The bottom line is that Judges do not like car dealers.The Judge is unlikely to know that an ABS sensor is not a big deal.I have unsuccessfully defended 3 cases brought by punters in the Small Claims Court where I thought there was no way I would lose.On the other hand I have won cases against an architect,a builder,a clothing wholesaler and the best one BCA.I think you will need to be able to prove that you offered a free repair and that they refused.Also it is important to make sure they have correctly followed procedure prior to issuing their claim.Was it sold with a new MOT,did you get a PDI sheet signed on handover,did you note the mileage when you had it back.How did you word your signed sales invoice . It is very unfair but selling cheapies these days is very risky and you might have to take your medicine on this one if you haven’t got a good defence which the Judge understands.