I'm not familiar with the phrase "overhead join", but we have the same practice here in Canada for uncontrolled aerodromes (you can see an explanation and diagram
here). At controlled aerodromes, we follow ATC instructions unless it is dangerous to do so, then we decline to accept the clearance (not a novel concept, I think?).
I have flown a bit in Oz, and as I recall they also use the "overhead join".
Sounds like the 'constant aspect' forced landing technique as taught in the military - and very effective, too.
I was taught this technique for practice forced landings in Harvards, and it seems to be easier than flying a rectangular circuit. I don't agree with flying at the edge of a stall, though ... I'd suggest flying at best L/D speed would be much more appropriate. Also there shouldn't be any need for 45 degree banks ... 30 degrees is plenty.