Access rights for group owners not working

I've owned land (well, renting it - but I'm listed as the owner in the parcel), and as you'd expect I can ban people, set media URLs and so on.

The land belongs to my alt, and the group is set to "Damien's Patch", a group I set up for this. It's not deeded.

I (Maxxi) am a member of Damien's Patch, and I'm also listed as an owner. I allegedly have the abilities to do things like set media URLs and ban people - in the "Abilities" tab, if I highlight "Change music and media settings", I'm listed as able to do that. But I can't.

Every time I want to change the media URL, I have to get my alt to come online to do it. Any obvious reasons why I don't have the access claimed?

Land needs to be deeded, not set, to a group for any group roles to have effect.