John Rylands Library
Anyone over 18 should be able to go in person to the library and listen to the tapes for free on some special "listening stations" created specifically for this purpose.
Their partial catalogue is available online as GB 133-DDA/2: Papers of Delia Derbyshire: Audiovisual recordings.
The library keeps the 1000+ paper from Delia's attic in its Special Collections. These are the same papers featured in the phone-camera snaps that pepper the WikiDelia and scanned in the Medialink library.
They used yet another numbering scheme for the items, which makes cross-referencing between here and there quite hard.
Their catalogue is available online as "GB 133 DDA/1: Papers accumulated by Delia Derbyshire".
Their catalogue is available online as "GB 133 DDA/1: Juvenile papers of Delia Derbyshire".
“Access to these collections are by prior arrangement only and users should note that the collection is subject to copyright restrictions. If you would like to use the Delia Derbyshire Archive please contact the curator, Dr Janette Martin (email: janette.martin[at]manchester.ac.uk)”
- Listening to the Delia Derbyshire Archive, 16 Feb 2016, in the Library's blog.