Just wanted to thank you again for the advice.
I went ahead and uploaded the KD8CEC 1.08 firmware to the rig, then successfully calibrated the uBitx.
I was able to make a QSO with a station on the east coast of England, approx 370 km's from my QTH which is 10km's north of Dublin, Ireland.
So a great end to the Calibration Twilight Zone. :-)
All the best, 73.