SOLVED. Book about an Australian girl and a psychopath in London [s]

[Francine]

I read this a few years ago and it is bugging me-the main character is Australian and she freaks out after suspecting she may have inherited the terminal disease that killed her mother. Instead of waiting for the test results, she spends all her money on a one way ticket to London and teams up with a group of squatters. She then gets a job in a leisure centre and only has one outfit to wear-she is constantly dressed in a netball skirt. The narrative then shifts throughout the book between her point of view to the point of view of a man whose identity is not revealed until the end, but is one of the squatters in the house that she knows. This man is leading a double life as a psychopath who has kidnapped a woman and keeps her imprisoned below the house the squatters live in. You are constantly trying to guess who out of the characters that it is. Can't remember the title or the author, or even the characters names, just that I really liked the story!!!

[Ann aka Iftcan]

How long ago was "a few years"? 2, 5, 15? Was it aimed at adults, young adults, new adults, children?

[Francine]

It was probably about 3 years ago, young adult fiction, I think

[Tab]

The Devil's Staircase ?

Do you remember the cover?
Time period story takes place?

[Francine]

THAT's IT! Thank you so much!!!