Well the compass I was referring to was the "E type?" compass. Liquid fulled and fully enclosed. Of course we had the standard RMI's with flux valve in the wing root' with comparater warnings when not boot strapped. Like all liquid fulled compasses it was subject to acceleration and deceleration errors, turning errors and compass dip.
To my mind it should be displayed at all times for comparisons sake alone, as it was and still is, a very reliable compass.