My experience. I had an older car, had just gotten 2yr nct, taxed for the year and thought great ill get another 2 yrs driving out of it. Got rear ended and car was written off, insurance offered €1200.00 and I argued it was worth more ( it was to me as I had no intention of changing it and was happy at to drive it for the next 2 yrs) I argued with them for a while but they wouldn't agree to repair it ( not financially worth it as it would cost €2600.00) so I asked how they decided the value. They gave me the engineers no who assessed it so I rang and he told me it was an average of the couple of cars he checked out on carzone etc. I did some research and came back to him, eventually got him up his assessment by €250.00 ( a lot to me at the time) insurance would replace the car, wouldn't fix it and withheld €500.00 which I had to collet from the scrap merchant that came to take it away so basically I doubt you will get much joy from them, though best of luck with it.