To delete a group you will firstly need to remove all linked users and programmes from the group. You can use the group filter option in the user tile to find out who is linked to the group: 

You will need to edit each user individually and remove this group from their user profile.

To remove a user you will need to click the edit pencil icon for their profile and then untick the group you want to remove: 

Once this has been done, you will then need to locate the group in the Group tile and select the edit pencil icon. Any programmes attached to the group will be listed in the Programmes field. There will be a cross option next to each programme which you can select to remove the programme.

Once all programmes have been removed you can save the group and then select the delete option which will be available on the right-hand side of the group:

Please note that if you are still unable to delete the group your account may be linked to it, and will also need to be removed from the group.