Is the weather going to be very different from early June? I went to Great Ocean Road 3 weeks ago (3rd-4th June) the weather was great! It was windy and chilly, and occasional shower at times, but the view was stunning. I haven't been there in summer days so I can't compare but I would still recommend it, it is definitly worth going during winter. The only disadvantage is the sunlight hours is a lot shorter than summer.