I have an issue with a 2008 A Class I sold with 50k miles and need some advice... Car was collected with no issues, had brand new MOT, no advisories, I also got did a PDI which customer signed saying al good, and I have a video walk round of car running, no lights on dash etc before handover. However customer called and said SRS Airbag light came on during drive home. I therefore agreed to take car back to be fixed which I did, I collected from them and dropped back. I put it on star diagnostics while I had it and it reported fault with passenger seat occupancy sensor, so I fixed before returning. Anyway, 10 days later I get a call to say light is on again, I have it back with the same issue again - it seems to come and go a bit. Question is am I obliged to fix this under the consumer act and or take the vehicle back and refund (ie does this count as a major fault?) bearing in mind I have MOT / PDI / Video to prove fault wasn't there before they took it. Also, if I have to refund, in the couple of weeks they had it they racked up about 900 miles, so can I charge this back and at what rate? All advice appreciated, I have never been in this situation previously. I would rather they keep the car and am willing to give them say £200 as a gesture of goodwill. They have taken warrantywise cover at the time of purchase, but didn't cover airbag system!!