However it might still be worth contacting the RNIB to express your interest.
A few years ago a blind member of AB (Woodelf) was asking if anyone here would be prepared to read and record the works of some of his favourite authors for him. Perhaps he might still be looking for assistance?
Years ago when I worked in a university, the RNIB came in and trained a few of us volunteers to read books onto tape for students using special machines. Every page number had to be included so blind students knew where they were and could include quotes in their work. Graphs and tables had to be described. So there may still be some need for educational texts to be recorded.