@tedmund , see my edited post above, your runs that had (0,0,1) for axis were wrong…
And of course ‘Rotation velocity’ should have its ‘sign’ set to right hand rule on (0,1,0).
I can never remember if that direction is with respect to the desired rotation of the geometry or of the air in the MRF, you can probably research that and post back here, or someone else can answer my query concerning direction…