Write-off valuation is well below market value

[peterw]

I wrote off a 2005 Toyota Avensis on ice at after New year. It had comprehensive cover. I see Avensis cars of that age, mileage, engine for anything from 8500 to 11500 on carzone and other sites. The valuation agency etwb are offering me 7500, which is lower than the lowest I've seen. Is there anything I can do to get them to improve their valuation ?