This was an old favorite and I was glad to find a copy of this recently in a local second-hand shop along with some 'Fear Street' novels.
I hadn't noticed before, but I was surprised to see this book advertised for a teen market instead of for middle grade The book's narrator Maggi takes care of her rampaging twin brothers, does the shopping, makes meals, and budgets because there's been no one else since her mother died. She is a companion to her father as well, providing support and humor and correction when she feels he needs it. Maggi spends a lot of time doing "women's work" in the kitchen, but its a point of pride for her. She's a 12 year old working class girl in England who lost her mom - yes this is 1988, but also - this is 1988. Even with those themes, the length of the book and some thematic elements skew the book to a younger audience in my opinion.
When Maggi's father gets a job offer to oversee repairs to a sprawling Victorian gothic mansion, it seems like a dream come true. He'll get his confidence back, the country will provide a place for the twins to run around, and best of all to Maggi, he'll get away from the trap represented by their vulgar "housekeeper". The house has secrets and behind it are a string of failed attempts to make it profitable. Is there a purpose behind the strange singing Maggi hears in empty rooms, in visions? What does the abbey want?
I read this a dozen time growing up, I loved the atmosphere, the British slang and vocabulary, the teddy bears, and the ending is superb. It avoids the cliches many haunted house stories end up becoming. As an adult I can see the social commentary is broad - questions of privilege and class are set up and even occasionally used for humor. Haunting stories need a good foundation to be effective and these characters - Maggi, father and the hapless Ms. MacFarlane in particular - make it worthwhile.