Going by recent experience with SWTSMBO'd clit .. they will over price the repair, and undervalue the car in order to write it off, as you are then only entitled to a hire car as a replacement for 7 days from when they write it off. If they were to repair it you have a replacement car until the work is finished.
It is therefore cheaper for them to pay out an undervalued sum and short hire car charges than a full repair and couple of weeks hire car charges.
Case law changed a while back, and basically you cannot insist the car is fixed if you can buy a replacement for the valued price.
Of course, the valued price is the problem ... they only use prices you have no access to (Glasses etc) and the FCO actually agree with the Insurers that an advertised price is not a true price .. you are expected to haggle !! and the distance you go is irrelevent.
If there is a car "they" think is suitable you are expected to go wherever, haggle ,and BTW .... colour is NOT a consideration.
You cannot claim for the loss of value for the Cat C/D tag, or the cost of the VIC that you'll need.
So much for the insurance putting you in the same position you were before the incident..
The whole thing stinks.