Many thanks Len – just the clue I needed. It seems highly probable that William Cowin was the son of John Cowin and Margaret Clague of Braddan.
William’s older brother John would seem to be the John Cowin of Mauritius and Thomas J and Orry Andrew were his sons. William probably worked with his brother in Mauritius before venturing to South Australia.
Orry Cowin sounds an interesting fellow and I can find little on him - if anyone can help, that would be just great.
Ross of Canberra