TLS 892

[hypotheses]

Last one (literally) 25D She agreed to Acton from sibling solidarity (4) ?N?E

[emeritus]

Anne (Bronte) who wrote as Acton Bell ?

[hypotheses]

Thanks emeritus - I had thought of that but didn't see how it fitted the clue. Your answer has prompted me to look a bit deeper and I find that, in fact, all 3 sisters published under the "Bell" surname, hence the "sibling solidarity". Thanks again for putting me on the right track.