Step 1. I've received a letter of demand but not an itemised invoice of damages claimed
It is not unusual that the first thing you receive is a letter of demand asking for a lump sum. If you have received a letter of demand but not an itemised statement of damages, it is advisable to ask the other party’s insurer for copies of itemised bills, photos, assessors reports etc. A sample letter to an insurer requesting documents including a itemised invoice of damages is available here. Be realistic! Remember fixing cars can be expensive! Whether it seems a bit high or the amount sounds right it is still a good idea to obtain an itemised statement of damages.