Thanks NTAp-AVS for your reply.
I'll ask NetApp support for more help.
To clarify, yes we do have 2 SnapCenters.
As per your details..
SCV Appliance --- Connected to --- SnapCenter Server A
NSM - SQL hosts -- connected to --- SnapCenter Server B
Server A backs up VM's and Server B backs up SQL databases on physical servers.
We want to add Server A (SCV Appliance) to Server B (SQL hosts) and be able to see all jobs from Server B (One SnapCenter).
SCV Appliance has a different website to NSM e.g. https://<FQDN>:8080 for SCV and https://<FQDN>:8146 for NSM.
So it looks like we should just log into Server B ( https://<FQDN>:8146), click hosts, Manage Hosts and then add vCenter, which will then see the SCV Appliance metadata.