Ok, now I’ve slept on it I’ve had another idea. I think clue 7 could relate to The Ritual. I didn’t get round to seeing it last year, but from what I understand the story is basically about a group of guys hiking in the woods that upset Norse spirits by entering sacred land. The reason for the hike is to remember a friend who was killed, and to help the group get over it and snap out of their stupor.
Sleight mean deception or cunning. Which could imply the clue is hidden in plain sight, and actually we should be thinking of “slight” which has the same sound, different spelling. A slight is when you offend someone, and a ritual is another name for an event that follows strict rules and procedures, and can be repeated throughout history. Rituals often take place when certain conditions exist (such as a full moon, or a certain time, etc).
Even if this isn’t the right answer, it’s good to find something new to discuss. Did anyone see the film? Was it any good?