Back in the saddle - need help!

Hello Rovers:
I am back on Ardurover after 5 years or so. I am attempting to resurrect a rover for use on our vineyard. I have a North RTK system. It uses a base station and the receiver is corrected over UHF. The RTK receiver is dual receiver with 2 antennas and provides precise yaw information even if stationary. The output is NMEA. MP shows rock solid position with correct compass direction. Get RTK_fixed

have a Orange CUBE APM running ArduRover 4.4. All compasses are disabled.

First question: what are the setting for this kind of GPS with yaw info ? Search reveals moving baseline but this is already done.

Problems:
Unhealty AHRS (does go away if AHRS_EKH_TYPE is disabled
FAILSAFE message - no idea what is causing this all FS_ options are 0
MP show vehicle at 90 to actual state. So going forwards and backwards makes it appear as if vehicle is going sideways

Any help much appreciated. Stuck at this point!