Chevvron, thanks for that, as I suspected I am a little out of date in that area. Historically however . . .
No 2 AIDU was established at HQ FEAF and like 361 Sqn were all part of our Empire. Given the long lines of communication to the Far East and the publication cycles it was probably deemed better to have a local aeronautical bureau.
With the Healey withdrawal from the Far East, 361 was never formed and No 2 AIDU was disbanded. That would have been at the end of the 60s or maybe as late as 73.
Why AIDU stuck to the Number 1 when the ANS reformed to embrace both the basic nav (2 ANS) and advanced (1 ANS) I do not know.