You need to get hold of the book "The Urquhart Brothers from Naust" as that thoroughly documents your lines of interest and related lines. This was compiled by Stan Urquhart and contains numerous photographs and much interesting information. I believe it is no longer available (sold out) but you should be able to locate a copy in one of the bigger libraries. Let me know if you don't have any luck as I have a copy and I can also put you in touch with Stan. He may consider a reprint if he gets enough interest.
Some of the original Urquhart family left NSW and settled at Whangarei Heads, Northland, New Zealand. The area they pioneered there is still named Urquharts Bay and is very picturesque. I strongly suspect they were related to the McGregors who had settled in the area a few years earlier, (about 1856), and that would explain why the Urquharts ended up there. Christina (nee Chisholm) Urquhart's mother's maiden name was McGregor and her mother-in-law's maiden name was also McGregor! Wouldn't surprise me if both Christina AND her husband were connected to the McGregors at Whangarei Heads! It was very common for cousins to marry in those days.
The McGregors at Whangarei Heads are my ancestors and they were originally from the Poolewe /Gairloch area, Ross-Shire Scotland, but spent 30 years pioneering in Cape Breton Island, Nova Scotia, before setting off to the Southern Hemisphere in 1851.
John Urquhart (04 June 1835, Gairloch, Scotland, died 26 June 1921, Williamstown, Melbourne, Vic, Australia) married Martha McGregor on 19 Dec 1876 in Auckland, NZ. She was a younger sister of my Great Grandfather, Capt Kenneth McGregor. John and Martha lived at Whangarei Heads until their old age when they moved to OZ to live with their only son, Capt Donald Urquhart, (of Craig Shipping Line fame), who was then Harbour Master of Port Phillip Bay, Melbourne. I have more information about this line if you're interested. My email address is kainui at bigpond dot com, (obviously you will need to use the correct format for the address).
Cheers, Jeannine (nee McGregor) from SW Sydney, NSW.