History House Greymouth has very kindly sent to me this advertisement from the West Coast Times issued on 15 March 1866. Once again, I know that my ancestor George Griffith was a violinist, and I know he was in this general vicinity in the period, so I feel it is likely to be my ancestor.
This is a further refinement of the time frame in which I know he was in New Zealand. I now know that he was in Hokitika by 15 March 1866, and he was still there in December 1867 when he was advertising as a piano tuner and repairer.
This is consistent with one of the periods in which he was absent from the Melbourne post office directories. He was listed in 1866, which would have reflected the year of 1865, and he was re-listed in 1869, which would indicate his presence in Melbourne by 1868.