Here are links to some pages you may find of interest:

Museums, galleries, historic houses etc with embroidered holdings

Victoria and Albert Museum, London

William Morris Gallery, Walthamstow

Ashmolean Museum, Oxford

Fashion Museum,  Bath

Museum of London

Kelmscott Manor

Metropolitan Museum of Art, New York

Boston Museum of Fine Arts

Winterthur Museum, Delaware

Dealers in embroideries

Paul Reeves

Esther Fitzgerald

Meg Andrews

Witney Antiques

Suppliers of threads, embroidery frames, etc

Au ver a soie

La tapisserie au point

De Vere yarns

Mulberry silks

Golden threads 

Benton and Johnson

Access Commodities Inc

Sue Hawkins upholstered frames


Textile Society (UK)

Royal School of Needlework

Embroiderers Guild

Jenny Adin-Christie Studio

Nicola Jarvis Studio

Jacqui Carey

Restore Products

McBurney & Black antique linen