Ah apologies Bunta130 and thanks to WIDN62.
I read it as blowing the main u/c down using the Aux System. Thought I was going mad and just went back through my old diagrams. But even using the Emerg NLG Lever surely this just unlocks the NLG allowing it to freefall, then the loady visually checks the down lock throught the viewing port?
It was twenty years ago mind, so could be wrong.