OK, so in the end the EPB unit has been replaced :( Ughh
We still have the vibration issues, definitely around 90kmh not all the time, and they disappear when accelerating.
I will follow up with the mech - but thanks all for the guidance through the EPB issues!
Just an update. Over time the vibration has got worse which has allowed us to diagnose the problem.
It is related to the Torque Converter which is a well documented issue.
The car has done 120,000 kms and we had the fluid changed in the transmission around 112,000km.
We have just had the fluid done again, and will see how that goes. If it continues it will be a new Torque Converter.
Likely to need a new converter i would say. Best get it sorted before it sends debris through the whole transmission....
Jc