Although you were not involved it is reasonable to request the details of the other 2 cars simply because "old lady" believed you were involved. Because she refused you her details you have grounds to go to the Police and report her for failing to provide details when reasonably asked to do so.

This all smells: as has been said someone is looking for a scapegoat. I wonder if "Old Woman" is insured?

Peter,
66, 2016 Porsche Boxster S
No longer driving Tarka, the 2014 Plus 8...