I want to insure a car that is a Cat D, (if your not sure what a CAT D is then please shut the door on your way out)
I was wondering If i get the car insured, how would the insurance company work out how much my car is actually worth, i know it's going to be a couple of grand cheaper than a non cat d, but how would they make a valuation? As I don't want to pay out loads on insurance each month, and then realise if it gets nicked etc i'd only get a fraction of what it's worth, and is there a specific insurance company that would be more likely to insure my car?

Check out the Trovit site for more info.

This is a bit tricky, I've insured Cat C&Ds and have found the best option was to go Third party only.
If you want F&T or Fully comp you can arrange to have an individual valuation and agree the value with the insurance company beforehand.
It does take a bit of time on the phone but is worth it.