Nimrod navigators may have been Gp 2 so as to grapple with legacy kit like the Kollsman sextant, Loran, and log on chart work, but were said to be really Gp 1.
I knew at least one Nimrod nav that went to GR 1 and another to SK. I have a vague idea of a FJ nav going Nimrod after losing his bang seat cat.
With a new maritime aircraft I suspect the ability to do a manual airplay and 3-star fix will be a distant memory for even the oldest still serving.