None of those things are actually illegal so they shouldn't be being filmed.
It is completely legal to film anyone in a wood or other public place.
It is also illegal to threaten people with violence.
If you want to engage in super secret rituals and do not want to be filmed then conduct your rituals in a private place.
Also, for the record, I think that blood letting rituals are creepy to put it mildly and possibly indiciative of an abusive cult. Not necessarily "satanists" but dodgy in the same way that websites that encourage people to self harm are dodgy.
If I saw a group of people covered in blood in the woods doing rituals I might try to film / photograph them and would definitely report it to the police if I thought abuses were happening or was unsure about whether or not they were.
Having said that there is a significant problem at the moment with SRA promoting grifters going out into the woods in an attempt to film "satanists doing rituals".
Some especially notorious ones have been grifting on gofund me and other similar websites begging for money for infrared goggles and cameras and other surveilance kit so they can "expose the satanists"
Some of these same activists are involved in advocating the kidnapping of children.
So this thread popping up here is highly relevant to my interests.
One thing I have been thinking about is that even after grifting thousands of pounds from gullible people the SRA promoters have never produced a shred of evidence of the satanic crimes they claim to be exposing. Then this thread appeared, which frankly is not evidence of anything at all but has been promoted as endorsing SRA CTs by at least one poster here. It is certainly an interesting coincidence