This site collates the various archives and manuscripts for sale on popular auction sites. It is not an advertising or auction site.
It is run by Dr Katrina Navickas, of the University of Hertfordshire.
Contact email@example.com if you spot any good archives for sale!
The lovely people at the National Archives have a tracking service for valuable or significant manuscripts that might be of interest to record offices and museums. You can read more about their work at http://blog.nationalarchives.gov.uk/blog/tracking-market-manuscripts/.
You can contact them at firstname.lastname@example.org