Heritage Open Day: Join Cliveden Conservation learn more about their work and have a go at making your own plaster moulding. As a company we are involved in the repair of traditional buildings and objects, conserving, repairing and restoring material from pre-Roman material through to twentieth century buildings and artefacts. The company is based at Cliveden Estate on the Berks/Bucks border. Established as an in-house studio by the National Trust, Cliveden Conservation is celebrating its 35th year. Still working with and for the National Trust including many properties in the surrounding areas, together with private country houses, cathedrals, churches, Oxford Colleges and many others. Work encompasses stone, plaster and the decorative arts.