Hi Gary-
Your dev site’s front-end should be visible without a login. For example, I can see your homepage, “our identity,” “our work” and “contact us” pages. Is it possible that the link you were providing was for a page that hasn’t been published yet? Saved as a draft or private post?
Another way you can get around this is to create user accounts for your reviewers. Navigate to the Users > Add New menu to set them up.