Thank you for your response.
I was thinking I had an option of accessing everything via web-browser if didn't have vCenter.
I've been reviewinghttps://docs.vmware.com/en/VMware-vSphere/6.7/vsphere-update-manager-671-install-administration-guide.pdf
and thinking "vSphere Web Client" is how I'm currently accessing the Host EXSi, which is not the case.
Now I'm learning that vSphere Web Client is a web-portal method to access the required vCenter if you want things like Update Manager.
Regards,
Paul