The secluded church of St Mary hides an extraordinary and rare scheme of sgraffito panels illustrating the Benedicte. The murals were executed in 1888 by the eminent Arts and Crafts artist Heywood Sumner and cover nearly every surface of the interior of the church. The panels were threatened by cracking, crazing, bulging, staining and delamination caused by moisture and salt movement and a trapping of water between the brittle cement murals and the soft stone wall behind. We carried out a detailed condition and recommendation report and a trial panel before an intricate programme of stabilisation and repairs to the three layer system, including grouting, micro-pinning and fine surface repairs. Detailed recording and trials formed an integral part of the project.