Thank you both for your information - it's great!
There is another Harvey Thomson/Thompson, who was from Invercargill and travelled up to Wanganui in 1871 to be the clerk to the resident magistrates court in Wanganui. I am yet to find out if he is connected to my Thomson family. I am still looking for Harvey's father, also named Harvey Thomson (born 1825), who I've lost track of after the death of his wife, Jessie Chalmers in Scotland. Going back another generation, his father (the original Harvey Thomson born in 1790) was an indigo planter in Java. An interesting family - other researchers had lost them in the mid 1850s - they never knew they travelled all the way to NZ. Would love to know what brought them out here - I wonder if they followed other family members?