car accidenr-total crash

On Thuesday I had car accident in Leicester. The other car was rented, and in that sytuation I don't know who is at fault in the accident. An insurance claim was never filed and no police report was made of the incident.
We were recently called by a collection agency representing a rent-company . We are asking for information such as a police report to prove their case.
Is the statute of Limitations 2 years in this case?