Sorry, this is a negative response, but with a reference you may not have yet. I find no reference to Suresh Pillai in the following article, which deals with that same subject:
From: INDOLOGY <indology-bounces@list.indology.info> on behalf of Sudalaimuthu Palaniappan via INDOLOGY <indology@list.indology.info> Sent: Friday, August 31, 2018 5:56 AM To: Indology List Subject: [INDOLOGY] An article on Kalabhras
Dear Indologists,
Someone mentioned to me that Suresh B. Pillai, the author of "Introduction to the Study of Temple Art" (1976),
also authored an article on the Kalabhras. Does anybody know the reference? I would like a copy of the article, if available.