Forum Discussion
So finally I got it working, I had to delete all the configuration and start again.
So I did run the gtm_add script first and then start by adding the servers then other components. At each step making sure the each component synced to the other GTM.
However I had to add the virtual servers manually as the auto-discovery didn't work. To add the virtual servers I used this format /Common/my_vs_server It seems to work because if the virtual server goes down also associated gslb pool goes down.
The following troubleshooting guide confirms that the virtual server auto-discovery does not support NAT: https://support.f5.com/kb/en-us/solutions/public/14000/100/sol14106.html
"Confirm that the BIG-IP virtual servers do not use address translation Auto-discovery is unavailable for virtual servers using translated IP addresses. Before troubleshooting auto-discovery issues, confirm that the BIG-IP virtual servers do not use address translation. For example, if the target BIG-IP virtual server IP addresses reside in a private network space, as defined by RFC1918, and are mapped to public IP addresses that are defined on a network device such as a firewall, the BIG-IP DNS system will silently disable the auto-discovery feature for the BIG-IP system."