The report of the 1910 death of Mrs John Alves in the Kent & Sussex Courier states that she had been living in Tunbridge Wells for about 6 years , which might fit with the 1903 journey. Other reports mention her only son Duncan and only daughter Mabel which made me wonder about the two children born in Australia. I've found the daughter , Caroline , who was born in 1861. She died in 1864 in New Zealand: 1864/8077 Caroline Alves 3 yrs. I haven't found anything about the son , William Davidson Alves.
Edit : William Davidson Alves coal company manager George Street , Dunedin , NZ 1881 electoral roll.