Perhaps it was intentional to add another layer of strangeness? I recall other movies where the setting is a little vague, presumably because the suits don't want anything "too British" to appeal to American audiences.
I thought the original two films were heads above most of the horror coming out at the time. Freddy and Jason were veering into self parody by then.
If you want really weird accents, check out the dubbed version of the original Mad Max sometime. ;)