Samantha Donovan: As thousands of Australians struggle to find safe, affordable homes, a new report from a housing advocacy group has found there are roughly 12 million spare bedrooms in Australia. Kathleen Ferguson: With a 72-year age difference, Marjorie Johnston and Sabrina James seem like unlikely housemates. Kathleen Ferguson: Rosemary Lawn from Homeshare Australia and New Zealand Alliance says sharing …