To those that might be interested ...
I installed OppenSSH and I only needed to make three changes to the files:
1. In "sshd_config" I changed the port number so that it didnt conflict with Dropbear as I wanted to run both for a short while.
2. I uncommented "PasswordAuthentication" and changed it from "yes" to "no" to make sure that only key authentication was used.
3. In "rc_opensshd" I commented out the firewall rule " ipfwadm -I -a deny -P tcp -W $INET -D 0.0.0.0/0 $PORT -y -o" so that the port was exposed to the internet (the whole point of the exercise).
Very simple and straight forward - in fact #1 and #2 were more my requirements than something I HAD to do to get it to work.
It just worked
I assume that I haven't left myself wide open with just these few changes ??