The company who insured the driver who caused the accident have accepted that he was to blame. They've assessed the amount owing to you and your partner as �1100 each and offered this as an 'out of court' settlement. If an out of court settlement is refused, then the matter has to go to court.
The court has to make its assessment based upon all of the facts placed before it. If only the insurance company attend, the court will only hear the 'other side's' case and, in the absence of any contradictory statements, would be likely to agree with the �1100 figure suggested by the insurance company.
The reason that you may be required to attend in person (rather than simply submitting documentary evidence about your injuries) is that the insurer's legal team may wish to challenge your evidence. (If you were being sued for something, you'd not be very happy if the person suing you could claim for a vastly exaggerated sum without you having the chance to challenge their testimony in court. The insurance company, similarly, have to be given the right to challenge your testimony).
Chris