I see that the British Library Journal articles from 1975 are now online. Among them I found a section on English embroidererd bookbindings.
The Felbrigge Psalter from the 13th-century is one of the pieces. It consists of two embroidered panels in Opus Anglicanum and measures appox. 20 X 13cm.
The article by Penelope Wallis says:
The Panels are worked in coloured silks and silver gilt thread – gold coated on silver and wound around a core of silk – on a twofold linen ground, a fine upper layer on a thicker lower one. The silk is used in split stitching while the metal threads are couched on the surface in a chevron pattern and as background. The colours are naturally faded and also destroyed at some time, when they were given a coat of varnish. However, where they survive they show greens, blues, grey, browns, fawn and white as well as a deep rose pink.
The front cover depicts the annunciation with the angel Gabriel approaching the Virgin Mary from the left. The scroll he is handing in his left was probably embroidered with Ave Maria. She holds a book, a motif dating back to the 9th century. The back cover shows the crucifixion with Mary and St. John grieving, while at the bottom a small figure may have been the embroiderer herself.
If you follow the link you can read the full article which has a number of images included. I think this is something you would have to see yourself to do it justice. I am going to keep diggin and see what else is in here.