What are my rights about the size of a courtesy car?

[oldknowall]

This is just the loss assessor trying to pare a few pennies off the claim to justify his existence. If somebody causes you to lose the use of your car, you are entitled to be placed in the same position as if your car had not been lost. It would be unreasonable for you to hire a Lamborghini to replace your Fiat Uno, but you are entitled to something that does a similar job. The fact that you could have managed with a smaller car is beside the point.

Put together a statement of all of your costs and expenses, including damage waiver on the replacement car, and tell the insurers that you want them to pay. Stand your ground and threaten to take them to Court.

 

[MaNi1]

Hi! I recently had a accident, where the third party is at fault and their insurance has accepted liability. I was given a courtesy car of the same size like mine. The courtesy car people have called me and told me that this is what I can have for this and this amount of time.
Now, the car has been given back, the third party says I could have managed with a smaller 1.0 car instead of a like for like car... The courtesy people are asking me to make a statement about these allegations.
I feel it shouldn't be my concern because they gave me that car, without even asking me, whether I could manage with a smaller car. They said, I can get this car without any costs, except the excess waiver and I took it under these assumptions.
My problem is now that I have been caused so many costs and inconvenience by this whole accident and insurance procedure that I really do not want any further costs and problems.
Does anybody have experience? Does anybody know what the law is here?