Groups are missing for logged in users

Good Afternoon

After any advice that anyone can give.

Recently installed Elgg V1.6.1 and all running smoothly. As Admin I have setup a number of Groups, however when a user logs into the site and goes to the Groups Page none are displayed.

If the user is made Admin, then they can see the Group listing and sign up for the Group. However, when they have Admin rights taken away they return to being unable to view Groups etc.

Wondered if anyone could shed any light please?

Many thanks