 John Grainger was an accomplished artist , with broad cultural interests and a wide circle of friends . These included David Mitchell , whose daughter Helen later gained worldwide fame as an operatic soprano under the name Nellie Melba . John 's claims to have " discovered " her are unfounded , although he may have offered her encouragement . John was a heavy drinker and a womaniser who , Rose learned after the marriage , had fathered a child in England before coming to Australia . His promiscuity placed heavy strains upon the relationship , particularly when Rose discovered shortly after Percy 's birth that she had contracted a form of syphilis from her husband . Despite this , the Graingers stayed together until 1890 , when John went to England for medical treatment . After his return to Australia they lived apart ; the burden of raising Percy fell to Rose , while John pursued his career as chief architect to the Western Australian Department of Public Works . He also designed Nellie Melba 's home , Coombe Cottage , at Coldstream . 
