Insurance and land

I have a question if anyone who has a similar situation a me, I'm a member of ArheryGB and obviously have the included insurance that comes with it when I shoot at the club, but I also own a 4 acre wood that I've placed a few small targets in to shoot at myself. I have woodland liability insurance but this specifically states that it doesn't cover activity sports such as archery, so does anyone know of available insurance that could cover the land for archery as most sports insurance companies only seem to do the individual.

I only wanted to have a small group of friends from the club (who are ArcheryGB members) for a fun shoot in the woods rather than at targets in a field but I'm a bit wary without appropriate insurance, does anyone have any advice or can point me in the right direction?