I know you can do this 
Probably published within the last 7 years
Aimed at girls aged maybe 8-10
Has a lilac cover
Plot is a young girl, maybe 10 who has recently moved house, isn't happy. The house is a bit unloved/ramshackle. She's not getting on well at her new school.
(possible there's a school play?)
Befriends a mysterious lady who lives in the woods. The lady makes her tea when she visits. The lady/witch counsels the girl about her school/friendship issues. My DD thinks together they have to lift a curse?
Random - the author had a baby a couple of years ago or so, as we looked her up on twitter when my daughter read the book.
Can anyone help? I thought the author may have been Abi Elphinstone or Abie Longstaff but it appears to be neither of those.