Thanks for the response Malcolm but my NX is the same as Phillip's, no mention of eCall in my handbook and no button in the light display. My manual does have a section 7 covering emergency procedures but eCall isn't mentioned. I can only conclude that the 2021 NX Premium Sport edition doesn't have it even though the official guidance says "If you buy a new model of car, approved for manufacture after 31 March 2018, it must have the 112-based eCall system installed."
So what has happened ?
Richard