It was biographical, the author wrote a book about her mum's upbringing. The gran was quite abusive and iirc the end was quite cathartic when the main character eventually escaped her gran's influence or whatever. It was (or some of it was) set in Streatham (London). Either the author was Marjorie somebody, or the main character was Marjorie.
I'm not even sure if it should be classed as adult fiction, or older childrens' fiction.... i was reading it as a teen.
No End to Yesterday by Shelagh Macdonald. The main character is actually Marjory! yay. The synopsis doesn't mention it being about the author's mother, but I'm sure it is based on her (her mother's) upbringing.