I think we can forgive MacColl a few spelling mistakes, like whiskey, etc. However, in that book, getting Mary Brooksbank's name wrong was rather more serious. Also, he didn't actually credit her with authorship of 'Oh! Dear me (Jute Mill Song'), saying only 'taken taken down from a manuscript submitted by Mary Brookbank [sic]'. This is at best ambiguous.                              

Mary actually gave MacColl the song and she could certainly spell her own name. In the 60s many regarded his words as holy writ.