Psychological/religious/spiritual horror film set in English rural house (2005-2014)

I saw this film on Film4 between about 2010-2014 from what I can remember. In it, a woman (pretty sure it was a woman) goes to a house in the English countryside after her child’s death (or someone she is related to) to overcome her grief/communicate with them. She is not alone in this house, as she is paying the owner a pretty penny to help her with this. The owner tells her what needs to be done each night and to follow their instructions perfectly. The woman is told the process will take about 30 days, and that she cannot leave or deviate from the instructions if she wants what she wants. A lot of weird shit happens, which I think are projections of how she is feeling. The main thing I remember is the ending: on the last night, she draws a pentagram (or something similar) onto the floor for some kind of ritual. She goes into the basement and nearly gets dragged into the darkness by other souls, but manages to crawl towards the light from the doorway. She ends up in a that is room completely white, with an angel at the end of it; not a regular angle though, this angel is huge, arching over in a crouched position, with rather disturbing eyes. All I can remember from after that is she finds a way to accept her child’s death.

I have scoured the internet trying to figure out what this film was called, as it was advertised all over Channel 4 at the time. I remember the poster being the woman sitting cross legged in the pentagram. I don’t think it was a Film4Production as I can’t find it listed but I might be wrong. I would greatly appreciate anyone who can figure out what this film is called. Cheers!