Hi Danny,

Correct me if I'm wrong here do you mean that you've configure the post permission(group) only admin can do it.
And you have add a stream module with story form enabled. But you tried to post a status using the module (story form) but it is not posting (not working)? If I understand you correctly here, seems like I cannot reproduce the issue
Perhaps, I've replicate this issue wrongly, can you provide steps by step how to replicate this? with some screenshots might help.

By the way, it could be best if you provide us with the access to the site, so we can try further checking how it works/reproduce the issue

Thanks for your cooperation and understanding.