I had initially run the below code;
Save-Module -Name VMware.PowerCLI -Path <path> -RequiredVersion 6.5.4.7155375 as per PowerShell Gallery | VMware.PowerCLI 6.5.4.7155375
But it appears it also downloads some modules with v10.* due to inter-dependencies.
I ran Save-Module -Name VMware.PowerCLI -Path I:\PowerCLI to get the latest and can confirm I have modules as you have advised above.
Since then, my VDS commands are working fine.
Many thanks