Cheers for the responses.
As it happens, I did try testing my last ride using the small ring with a straight chain line. Can confirm the reduction in noise.
Also easier to flit from high cadence sweet spot intervals when dropping to the rest phases. Seems to be less of a spin down which I assume is due to the flywheel spinning at a slower rate even though my cadence remains high.
Another thing I have noticed is that the mileage that it reports is lower when using this lower gear. Again, I assume that the slower flywheel is the reason behind this?
As for workout being achieved, can I assume that this would be the same when using ERG mode, no matter what gear is in use?
Basically the trainer adjusts the resistance and I end up doing the scheduled power and the aimed cadence and this is the same regardless of chosen gear?