Do not claim from the third party directly. When the at fault party is advising how much they are going to settle for it is a conflict of interest and you have no means of recourse in the event of a dispute (i.e. you cannot go to either the financial or legal ombudsman if something goes wrong). Accident management company is the best route because they have no conflict of interest.They also act directly on your behalf and you have nothing to pay this way, i.e. no excess etc. Using your insurer has it's pros and cons. You will have to pay your excess, it will affect your no claim bonus until which point the claim is finalised and it will affect your claims history. They may not provide a hire car for the full period of the claim, only a courtesy car for the period provided by their approved repairer. You may well find they refer you to a credit hire organisation anyhow (they earn money from referring you),which defeats the object of not using an accident management company directly. But your insurer will/should provide a fair market value, pay out quicker and you have a right of recourse via the financial ombudsman should you have a complaint.