Southern Celt and Azizi,
We have quite a collection of phrases with similar meaning to the "half a bubble off" and "not twisted right" ones.

Two sandwiches short of a lunch
Two bricks short of a wall
Not the brightest crayon in the box
Not the sharpest knife in the drawer

are some that are probably well known outside OZ and may have originated almost anywhere, but
He's got kangaroos loose in the top paddock
is almost certainly of Oz origin.

Frank, the original poster, made reference to New England. Where I live, many older people refer to the area as "the New England"; the definite article specifying the definite article, so to speak. And there's a collection of Australianisms, of the sort Frank seemed to be interested in, linked to Mudcat's home page

Cheers, Rowan