The blame for this particular speech inflection is being laid at the door of Australian soaps, and the students who watch them! It's true that Australians do speak with a slight lift at the end of some sentences, but for some reason, this appears to be exagerated in the characters of Antipodean soaps, and it sounds even more pronounced when spoken with an English accent. Speech oddities like this are the result of modern communications - people hear regional accents far more via TV and radio than they did years ago, and people move around and travel far more now than they did. Jamie Oliver Is responsible for the advent of certain Estuary English phrases, and comedy shows like 'The Fast Show' have ensured that certain phrases and expressions have entered the national conciousness. Hopefully the particular irritant of which you speak will pass on and out of general usage. I hope so (?)