Is the land truely private? Eg farmland is part of a business and not construed as private
Are you preventing anyone from accessing the land even if they are trespassing?
Eg fence off, put up safety signs etc
Is it a sufficient distance from public highways?
Legal yes, not necessary safe and a good idea
The landowner and you (if not owner) become liable for any incident
You need all the facilities, netting etc, chronos, safe areas, control of people masking up & making safe, plus good relations with the neighbourhood