Legal advice regarding selling a vehicle as a trader

As a motor trader I have sold many car's and never had complaints. A gentleman has contacted me 2 months after the sale of a car and is asking for nearly £3000 which he has just paid out to get the car fixed. He has straight away threathend me with court action rather than giving me a reasonable opportunity to solve the problem. When he first contacted me with the complaint I offered to take the car back and have it looked at a garage I use, with a view to a repair or full refund. I require help as to how to deal with his threats of court action etc.