thanks for all the responses!
well spotted sean! my bad - so when truing to add the air hole to the diagram I think I must have picked it up the wrong way round… oops! sorry!
air hole is right thumb - highest note right hand pinky
aybee - i've gone back to the keyboard to have another listen. If we're looking at the same key (left hand pinky with the arrow pointing to it on my diagram) its definitely a low D (octave below middle c) on the push and a step up to the B♭ just below middle c on the pull)
i'm liking the idea its a tone lower - If I want to hum along to myself, baritone who struggles with the high notes!
thank you everyone, will amend my diagram with Don's advice re duplicate notes to have a somewhat more working note map!
am I right in thinking that the first key of the left hand middle row tells us the tuning for the instrument? (sorry this is definitely day 1 teaching & learning stuff!)