The key issue is the relation of the drive system to the measurement point. Is it fixed or can it vary? The answer differs for suspended subchassis v non-suspended. The non-suspended answer doesnt change if you mount the whole thing on external isolation.

I have turned the volume up to full - I can hear no motor noise.

I dont know the vpi and the verdier so I cant comment.

Motor noise is easy to check, when I said I turned the volume right up I used an unmodulated track on a test record not music. If motor noise existed it would be buried in the music otherwise.

I am sure you wouldnt notice anything with respect to the sme linn vpi etc but it still exists. It affects the ability of the measurement system in ways that are less obvious than simple pitch stability. Which is why the BL sounds much more dynamic, detailed and has a killer bass.