Hi David I also am researching Maxwell family for a friend Agnes Maxwell's parents were James Maxwell married Agnes McKay I do have info of this family you can email if you are still interested I am willing to share what I have . As a widow In  24 Nov 1874 James Maxwell (SNR) ,travelled from Glasgow to NZ in the ship called "Auckland". He is listed with 3 of his grown children, James (JNR) 24, farm Labour  Alexander 21 farm Labour and Agnes 15.Domestic Servant and settled in Dunedin . He had followed his Daughter  and Son in-law Jane and John Cloggie Wyllie as they migrated to Dunedin New Zealand in 1873 the year before on the same ship