The Unitarian Universalist Association has sold three of its Beacon Hill properties at 25 Beacon St. and 6-7 Mount Vernon Place to a Boston-based LLC for $23.6 million. The properties were sold to SDC-DLJ Beacon LLC, a partnership of DLJ Real Estate Capital Partners, Sea-Dar Real Estate and CNW Capital Partners LLC of Boston. The sale closed March 20. UUA’s Beacon Hill real estate included a 28,494-square-foot building at 25 Beacon St., next door to the State House, which has served as the Unitarian…