Could it be that Carl left Copenhagen in 1877 as "Carl Chr. Vilh. Bockmann" but arrived Sydney, now married, in Sydney in 1882 as Carl Mattinson Bockman:
Inward passengers on Steam Ship "Garonne" of Liverpool (3876 tons burthen; Henry Y. Slader master) arrived Sydney 28 June 1882 from the Port of London: Mr. C. Bockman (Gent) and Mrs. Bockman (name not given).
NATURALISATION (As a British Subject in the State of New South Wales): Carl Mattinson Bockman, Engine Fitter, of Dibbs Street, Alexandria; Age 46; native of Copenhagen, who arrived in 1882 on the ship "Garonne" was naturalised 10 Sep 1903.
Carl's wife could have been Annie W. Bockman (née ????).
Is there a website giving births, deaths and marriages in Denmark? Can Carl's parents Jeans Peter Bockman and Marie be found?