I just did a search for them and no-one seems to have answered Murray's initial question from 1999 (apologies if I've missed it).

I'm fairly sure that the band who had the big hit with this song in the 60s was The Seekers - with Judith NOT taking the lead for once. I think that's Keith singing but I may be wrong.

here

And here is a version (eventually) with new lyrics by Anne Wooby relating to

The Napoli