A few warnings that I've picked up over the years.
The police are not the least bit interested civil liability, they are only interested in any criminal proceedings and anything they say should be taken in that context.
They know very well that they will only be successful in securing a criminal conviction if they have enough evidence to satisfy the case "beyond reasonable doubt".
Someone could be acquitted of a criminal offence (often through lack of evidence) but found liable for civil damages because the civil system works on the "basis of probability" (an example being OJ Simpson).
Furthermore insurers want to come to an agreement themselves without the costs of going to court.
What I'm saying is that what the police have said should not be taken literally to reflect what a civil court or an insurer would decide, because each has difference priorities and works in a different way. The insurers priority (both of them) is to settle the case in the cheapest way for them and not necessarily the fairest.
Also I would add a note of caution about credit hire vehicles which is not the same as a courtesy vehicle you are entitled to as part of your insurance.
Sometimes it's not even clear exatly what you are being offered.
Credit hire vehicles are offered at expensive rates, but you often have to sign a contract that says you may be liable if they costs are not paid by the insurer.
If it works out for any reason that the case goes against you or the insurer refuses to pay the ludricrous charges then you can find yourself faced with a large bill.
So I would say make sure you know what you are being offered - is it a courtesy vehicle with no charge as part of your insurance policy? or is it a credit hire vehicle with liability on yourself? You need to read the paperwork and not believe what you are being told (unfortuantely).
Best wishes with both the recovery and the insurance.