Howdy yourself Graeme.
Yes it is the GAC-100. Looks like it got to the mock-up stage , but no further. Several references in Flight, including:
1969 | 3111 | Flight Archive
Looks like GAC were also expecting some military interest judging by this model:
I see it was mentioned in another forum, so maybe that's where you had the thought from Irishair? It had been incorrectly referred to as Australian!
Talking of Australia....Noyade has control
