Why did my neighbour take his car, which I'd damaged, to be repaired at an expensive garage?

My next-door neighbour's relative's car was parked on their drive, and I reversed into it and just scraped the side, and took a chip out of the light unit. I offered to pay for the damage done out of my own pocket, not wanting my insurance premiums to rocket. My neighbour’s relative went to a franchised dealer and got a quote for over £500, which I thought was very excessive for the amount of damage done. (The dealer contracts the bodywork out to another company.) I asked if he could get another couple of quotes to see if the quote was actually comparable to others as I have no problem paying for the damage but I wanted to pay a fare price. He point blankly refused to do so.

Therefore, I went to two garages at random and received quotes for no more than £300 for the work done, to include the light unit. I emailed him back to inform him that his quote didn't seem comparable and didn't hear back. A week later I received an email telling me he will be picking his car up in the morning and that he will be posting me the bill. He had taken the car without me knowing and got the work done and paid for it. Now he insists that I reimburse the cost even though I never agreed to it.

Asked on 10 February 2011 by AM, via email

Answered by Honest John
This is the reply from our legal people:

“The injured party is under a duty to "mitigate losses" - which means the work must be done to an acceptable standard at the lowest possible price. You obviously admit there was some damage and as you informed him of others willing to do the work for less money, that is the price you should pay. The court would probably find you owed him £300 but if he insists on taking it to a particular repairer then although he has the right to do so he must pay the additional amount (£200) on the bill.”
Similar questions
The boyfriend of my neighbour's daughter damaged my car lightly. As all parties agreed it was minor damage, I said I'd get a quote and we'd get him to pay the repairer on the day, I had him booked in this...
I bought my wife a new Honda Jazz in September 2012. On Wednesday, she was driving along an unlit road when she hit a pothole with her nearside front wheel. It was raining and visibility was poor. The...
In December 2016, I purchased a 2015 Ford S-Max from a Ford dealer. The vehicle was Ford Direct with a two year, unlimited mileage warranty. Recently my car was hit by another vehicle. When I took the...