I was not aware of the "'Aha' she cried" beginning until reading
this discussion page ... for me it was always : Too late she cried
as she waved her wooden leg". This saying seems to have been here
in NZ since the 1920s I would think. I had a chat about it with
the late Harry Orsman, Editor of the Oxford Dictionary Of New Zealand
English, and he proffered the view that it was some kind of satirical
'take' on men asking ladies for dances and the planned assignations
being jotted down in notebooks. But ... who knows!