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We have included a short biography of our committee members below to illustrate the diversity of the team that represents many of the disciplines associated with the conservation of Historic Interiors.   


Christine Sitwell ACR

Christine trained as a paintings conservator at Winterthur Museum, University of Delaware before embarking on an internship at the Tate Gallery, London. She joined the National Trust in 1990 as a paintings conservation advisor responsible for managing and organising the conservation of the Trusts' collection of paintings and also advising on historic interiors with regard to paint analysis and conservation of painted surfaces.


Lisa Oestreicher

Lisa came over from her native Canada in the 1980's to finish her studies at the Bartlett School of Architecture and the Architectural Association. After several years working at Westminster City Council as a conservation officer Lisa went back to specialise in architectural paint research as part of the Royal College of Art/Victoria & Albert Museum conservation training programme. Lisa has been involved in the Historic Interiors Group since its inception.


Helen Hughes ACR FIIC

Helen is one of the founder members of the Historic Interiors Group. Since 2009 she has worked as a freelance Architectural Paint Researcher. Before this she headed the Historic Interiors Research and Conservation Unit of English Heritage for 25 years. Helen holds a degree in the History of Art & Architecture and Easel Painting Conservation and is an ICON Accredited Conservator-Restorer and a Fellow of the International Institute of Conservation. She has worked on a wide range of historic interiors projects and also teaches conservation history and theory at several universities in the UK and abroad.

Sandra Howe ACR - Treasurer

Sandra trained as an objects conservator at DeMontfort University and has been working for the National Trust since 2002 as a regional conservator, currently based in York. Advising on preventive conservation, commissioning remedial treatment of objects and promoting the balance of access and conservation in historic houses. Sandra joined the Historic Interiors committee in 2012 and has been treasurer since 2015

May Berkouwer ACR

May trained as a textile conservator in Amsterdam (1980-1984) before working at the National Trust's Levy Textile Workroom and Ksynia Marko's Textile Conservation Studio in London. May has been independent since 1992 setting up her own studio in Suffolk in 1996.

May and her team work on a wide range of interior and ecclesiastical textiles as well as tapestries, embroideries, flags, banners and costume. May was PACR accredited in 1999 and has been an assessor for PACR since 1991; she joined the Historic Interiors Committee in 2012 

Heather Tetley ACR

Heather worked at The Carpet Conservation Workshop, Salisbury (1988-1996) undertaking conservation of historic carpets for historic houses, Royal collection and private clients before opening The Tetley Workshop, Devon in 1996. The Tetley Workshop specialises in all aspects of the conservation of historic carpets in historic houses and private collections; including a Royal Warrant Holder to HM The Queen for Conservation of Carpets.

Allyson McDermott

Allyson trained in conservation of fine art and art history in Newcastle before working as lecturer in Conservation of Works of Art of Paper (1981-1986), Head of Conservation Studio at Sotherby's (1990-1995) then advisor on Paper and Wallpaper to the National Trust (1999-2004). Allyson started Allyson McDermott Interiors in 1980 as conservators of historic interiors and specialists in the conservation and reproduction of historic Chinese and Western wallpaper.

Charlotte Owen

Charlotte trained as an objects conservator at Lincoln University before joining the National Trust as a conservation assistant and project conservator (2009-2013), project conservator for English Heritage (2013-2014) and Cambridge University Museums (2014-2015). After a short stint as a freelance project conservator Charlotte joined Hirst Conservation as an architectural paint researcher, she has been a committee member since 2015 and manages web content.

Rosie Shaw

Rosie trained in Fine Art Printmaking before studying Historic Building Conservation. She worked as a freelance conservator before joining Hare & Humphreys as an architectural paint researcher and project manager. Rosie is currently working as a freelance member of Lincoln Conservation and also as a Project Manager for the London Historic Buildings Trust. 

Rosie joined the committee in 2017.

Benedict Ryan

Benedict studied a BA. in Conservation and Restoration and then went on to do a Masters specialising in the conservation of historic interiors. Following a short stint working in the Middle East he started working for Hare & Humphreys as a conservator. After a few years of site work Benedict moved into conservation project management within the same company.

Benedict now runs a conservation, restoration & specialist decoration company based in central London.

Benedict joined the committee in 2018.

Ayaka Takaki

Ayaka is an Architect, accredited with Specialist Conservation Architect (SCA) and Architect Accredited in Building Conservation (AABC), and specialises in the repair and conservation of historic and listed buildings. She is currently working for Donald Insall Associates as an Associate. She understands the intricacy of working in historic buildings and has experience of managing the logistics and expectations of end users and stakeholders, from project initiation to post-completion.   

Ayaka joined the committee in 2018