Great news .
So did you manage to fix it and work out what the fault was ?

No, the error is not fixed yet. Progress is kind of slow due to weather and that my spare car takes care of the daily commute.

Yesterday evening I disabled EAS using Build Mode setting and manually raised the car from bump stops. Today the rear was lowered and that indicates that there is a minor leak in addition to the sensor related problem right front.

I will post updates when there is somhting to report. 

No leak in the rear. Only Build Mode that somehow was disabled and the EAS self-adjusting based upon erratic input.
First trip in Build Mode was accompanied by an anoying warning chime every minute. After a stop at at a chop the warnings silenced. 

It took some time before this fault was fixed. Build mode worked too well...

It turned out to be a broken wire to the front right hand sensor. Replaced the connector and wire with the readily available repair kit.
Diagnosing the fault was hard as the fault was intermittent and errors on compressor and gallery pressure appeared. Apparently as the EAS couldn't figure out how to adjust the ride height. Finally the signal from the sensor was permanently lost and then the fault was easy to spot. Terrain response display showed the wheel all the way down even if it was not...