AWB 34-008 details the compass calibration requirements of aircraft with a certificate of airworthiness.
I note that it stipulates engine(s) running and all systems operational.
How does that compare with doing it on a non ferrous trolley and engines off?
Of interest to Dick Smith is the paragraph that allows you to have a system of maintenance that stipulates a different elapsed time for compass swing.
I note Arnold E has carried put the "new' 100.5 requirements on light aircraft, the price your compatriots are charging is outrageous, especially out here in the bush. Nearly $6000 all up to get two light helis done, took less than a day.