Insurance is a b***er. The usual rate is £5M public liability and that costs £300 per year using the 28 day rule ie, roughly one week-end once a month. These are the same rules that enable car boot sales to operate.
Most land owners insurers will either shy away from this or insist.... if you are lucky enough to get permission that you have £5M liability cover to match theirs. That is the hard bit.....You have to be covered too if you are a group. So, unless you are a teaching group, or a 'Club' abiding by a set of rules that a club is obliged to. You may be lucky with that one.
Friends, well there are folks enjoying themselves in woodland belonging to friends and they sure keep that quiet!
Or Scout land. Where you have to be 'suitable' to be near young people.
I hold one 'Hoot' a year to contribute towards my liability cover and the other times now are by invitation only.
I hope this helps.
Swyn.