In my blog I have posted the details of the murugan temple at Thiruvidaikkazhi (திரு இடைக்கழி).
This temple is situated at 6 km. from thirukkadavur, its a famous murugan temple having the sthal virutcham Kura tree a rare species. The sthala puranam says this is the place where the Nichayathaartham (betrothal) was happened for muruga and theivaanai.... for more details and photso please follow this link http://svprsk.blogspot.com/2008/09/thiruvidaikkazhi.html
You are correct this is siva temple to but the sivalingam is behind the murugan statue in the moolasthaanam. Again you are correct senthanar has sung on this Eswara..