I am getting my head around OG and its permissions. I have a user (not super-user uid=1) who can create OGs. Rather to my surprise, when I look at the OG members, the user who created the OG is there as a member but has not been given the "Administrator Member" role. Yet he seems to have full management rights on the Group rather like a local super-user. Does this mean that he should create an "Administrator" separately?
I should have seen this myself. In fact the answer is in the slightly obscure "OG Settings" (Config > Organic Groups > OG Settings).
In this there is an option called "Group Manager default roles" which is applied to every OG content type. This allows you to "Select the role(s) a group manager will be granted upon creating a new group"