Where are you goig to base yourself ?? Meridian Dive Centre in Durban, South Africa possibly does arranged dive trips to Mozambique and I know that there is great diving there !!
You can get hold of Barry & Celia Coleman there, contact via e-mail firstname.lastname@example.org -- They are really great and highly qualified !!
Check them out on http://www.scubadivesouthafrica.co.za