Australia's Eurocats 2000 system (similar to NATS) has all the enroute consoles oriented to true north, and our bearing/range line thingie reads in degree true also. To give an aircraft a heading we visualise the true heading and convert it to magnetic, just to avoid confusion when the aircraft converts it back to true.
Egad!
Why use true on the consoles? For example we can have variations of more than 24 degrees east AND more than 27 west on the one console. Usually a bit less than that, but, and he doesn't do much vectoring.