prepare to have an absolute pain in the balls with the insurer, i bought my zed after hitting some oil going past the docks in belfast and skidding at about 25mph up a kerb and head on into a 14ft wall in my hyundai coupe (was grand rescued my footy gear, all good)
they got back to me within 2days of the crash saying it was a write off and had offered me £4700 and had posted the cheque already "in case i'd accept it" , your car being immaculate, servicing you've done to it recently, changes you've made mean absolutely nothing, neither will the fact you said "car is valued at £x" when you signed your insurance and it effected your premium.
whatever model/age/miles it is and that came with it as standard is all that matters and how much it will cost to replace it the same model/milage/age for within 70miles of your address basically.
whatever they offer you contest it, and then keep chasing them to hurry up, basically they work on "inconvenience" and offering you around enough that it's less than you want but close enough you will take it on the chin rather than be without a car for #x weeks. (you've a hire car and it was someone elses fault so you're in a better position than most, i had two other cars to use so i was alright in this stage too)
i had to send them 3 examples of models (from traders remember...which is a bonus) of why their evaluation was inaccurate, which i did, sent them three examples local to me of cars with similar age/spec/model at 6k or there abouts, they replied with i s**t you not , two examples, one had a smaller engine and 30k more miles, and one was an automatic and 3 yrs older :lol:
got an extra grand in the end.
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oh yeah and if you fitted anything non standard but still have the factory bits, go and rip it out those parts of whatever recovery centre it's in and leave the factory bits and bobs ont he floor (audio equipment or whatever)