V enjoyable and well-made movie

Wanted to day how much I liked this movie it would be in my top 10 of horrors - acting is excellent (nice to see old Littlefinger from Game of Thrones in a different guise) as is the filming and plot construction. I like that it ends properly and does not fizzle out like some other horrors, which start well but quite often seem to loose the plot and end going nowhere ... It is obviously of a more simple structure than, for example, Martyrs, but works v well as a Brit-flick type of experience. I would put it in the same sort of vein as Triangle (one of my other favs) in that the viewer only finds out what is going on as the film progresses which gives a good feeling of unease and suspense the first time it is seen, tho some of it made more sense to me on the 2nd viewing ... 10/10 will look forward to more from this team, fingers crossed?