Diagnose whirring noise in front diff WG Jeep Grand Cherokee

I get a loud whirring noise upon deceleration, faster = louder, but no noise when accelerating.
Both front wheels are off the ground during the assessment and hopefully I have covered everything while under there. When I spin the wheels fast and say there is no noise, well the noise that you can hear is only the RH tyre rubbing on a fold of the plastic tarp that I am lying on.
When I was checking for pinion and uni play I was exerting maximum force that I could to ensure best outcome from test.
Also to note that since fitting both new cvs I have done all the usual testing afterwards and they are both sweet. As silent as they could be and no play when checking under car. All brake components were also secure and not excessively worn so I am comfortable with ruling those items out of the equation. Hub bearings are also in very good condition.
Tyres are all good and recently checked but this noise is definitely mechanical noise, not rubber tyre related.