Hi Derek, just came across your post while Googling.
I am descended from Walter Blackie bc 1770 possibly in East Lothian. Then from him and Margaret Cowan to John B b 1792 Saltoun; then from John B and Susan Gourlay's eldest son Walter b 1816 at Haddington.
That Walter who married Margaret Jack called his 4th son Walter but the elder Walter didn't have one himself; whereas his four brothers, including my GGF Andrew, each named a son Walter. These men were born in Haddington, Dalkeith, and Liberton.
Andrew's son Walter B was born in NSW, Australia and he too had a son called Walter b 1909. That Walter had two cousins named Walter both born in New Zealand in 1903 and 1904.
The spelling didn't change in Australia and New Zealand.
regards, Carole