Accents were all awful
With the exception of Jo's mother. Whoever wrote this clearly didn't put much effort into researching British language, there were a lot of Americanisms in there (or Canadianisms, I should probably say).
shareI'm English and I thought Poppy's accent was fine. She actually imitated Jo's inflection and voice very well. I was shocked because I had seen an older interview with Jo Rowling from 1999 just a little before watching the movie and it was really jarring to see that Poppy imitated Jo so well. It was like literally seeing the woman, but in another body.
And Americanisms have nothing to do with accents.