Thank you JA
OK - in the past, (but it has been a wee while)...... I pull up a presentation from any iWork App, on my pad. Then with the Apple TV box, on - which is - connected and tuned and incidentally, working for everything except an iWork presentation - to the HDMI screen. I scroll up from the bottom of the screen to get the 'AirPlay bit' and select the device (HDMI Screen or whatever else its been called) scroll up a bit more to be certain that 'Mirroring slide thing' is selected on (to the right (Green)) Usually at this point the pad screen is mirrored to the screen - it isn't!
I've reset everything, iPad, HDMI Screen, all the settings for Apple TV, in accordance with the Apple TV instructions and no presentation and no mirror! Checked everything for updates. More to the point I have to delay the 2 senior Type Rating Captains who have come a very long way to see a presentation because I can't get the presentation on the screen!!!!!! (Not that the last bit is anyone's fault but my own for presuming that something that once worked; still did).
I have solved the interim problem now (Smiley face) by showing the pres using my phone but I can't read my notes because the screen is too small!! So perhaps not a slick as I'd hoped. I can now sort this problem out in slow time with yet another visit to the Apple store in town.
Thank you so much for taking time to try and offer help as you always do.