New Zealand's top three wine companies are all facing major changes in ownership, all revealed in the past week.Australia's second largest wine company, BRL Hardy announced tonight(Friday) that it plans an offer to take full control of NZ's third largest wine company, Nobilo Wines.The announcement follows yesterday's announcement by the DB Group, NZ's second largest brewer, that it plans to sell Corbans Wines, NZ's second largest wine company.