I had been to this temple with Prof.Swaminathan and our Sankarnarayanan. The temple belongs to Uttama Chola Period. There are several miniature panels starting from the balipeedam. There are many panels on the adishtanam. The temple structure was in good repair. I did not feel from a structural point of view, it needed any rework. Kumbabishekam can be done without disturbing the structure and sculptures. This is currently under Aranmanai Devasthanam, so I am confident that adequate care will be taken in terms of its preservation. The temple has a large perimeter wall and the clock is on this wall. I am not sure about its antiquity though. The temple has a lot of inscriptions specifically from Uttama's period. Here are the photos from this temple. https://picasaweb.google.com/105017052378989894996/Thiruvisainallur#