Dear Sankar Sir If you mention about the cave temple in Pudukottai Dist.between Keeranur and Killukottai. There is a village Kunnandarkoil and 12 kms from it there are two cave temples on the hills of Tiruvalandur. one for Siva and another for Vishnu. They were carved by one Kuvan Sathan alias Videl Vidugu Mutharayan, an offier of Dandivarman (775 - 826 AD).
It this is the cave temple you are mentioning, I can provide some little details. Kindly inform.