I am a private seller. I sold my car to a garage (trade) and now they want to return the car and threatening legal action for selling car without telling them it was involved in an accident. They did an HPI check and confirmed it was all clear of accidents and finance. They paid a deposit online then came to view and try the car on a Saturday afternoon. Price was agreed, they took the car and I gave them till Monday noon to pay the balance (accounts issue). Balance was paid later that day (Saturday). Monday they phoned saying that the car was un roadworthy and the roof airbags have been deactivated/removed which they could not tell on initial inspection. I had no idea of the airbag situation as I also carried out an HPI check when I bought the car and all was clear. Where do I stand?