The following materials are being offered for sale by  Richard Ford, a bookseller in London for £3000.00 (ca.  $4537.05) . Book Description: [1976-1990], 1990. The Mother, the Neighbour and the Black  Hand of Ted Hughes A small archive of material deriving from the papers of Professor Trevor  Thomas, Art Historian, occupant of the flat below that of Ted Hughes and Sylvia  Plath at 23 Fitzroy Road, Primrose Hill, London.  It includes:   a. Two Typed Letters Signed from Sylvia Plath's mother, Aurelia, airmail, to  "Professor Thomas", detailed, 7 & 28 May 1976, one with handwritten date the  other with a handwritten PS. 7 May 1976: She is responding to the haunting contents of a long letter from  Thomas, convinced that Sylvia would have left letters for her family which she  quotes Thomas[?] as saying were "destroyed when found". She comments that many  inaccuracies have been written about Sylvia's work. For example The Bell Jar  wasn't autobiographical...
Sylvia Plath Info Blog by Peter K. Steinberg. The blog of A celebration, this is.