Hi All
Just as an update on this, my vehicle appears to have gotten worse. I'm not getting severe car rattling vibrations (like driving over a cattle grid) on light acceleration on speeds from 30mph onwards
It's almost as if the car is trying to go into too low a gear. I can get the lightest hint of it in manual mode, but that generally behaves better. Behaviour at 70mph with a more subtle vibration remains.
Only change I'd made recently was going to the eco tyre pressures to help lighten the steering but the problem persisted at the lower pressures too.
I think it's going to head off to the dealer.