Redfern had expected to succeed D'Arcy Wentworth as principal surgeon; Macquarie indeed recommended him for the position in 1818 — however it was given to James Bowman in 1819. Redfern immediately resigned from the Colonial Medical Service and later in the same year Macquarie made him a magistrate, but this was objected to by Commissioner Bigge and the appointment was not sanctioned. Redfern had a large private practice as a physician, and though somewhat brusque in manner was much liked and trusted; he became the "best" and "best-known" surgeon in Sydney. He visited England in 1821 as a delegate for the emancipists endeavouring to obtain relief from legal restrictions arising from a court decision in London, which came in the form of the New South Wales Act of 1823, allowing ownership of property and "personal action at law" for those who served their sentence in New South Wales and were no longer prisoners, the emancipists. In January 1824 he was at the island of Madeira for the benefit of his health. His wife, who was then in London, made application on his behalf for an additional grant of land, which was allowed. He was evidently then in good circumstances. In 1826 he retired from practising as a physician, and for about two years engaged in scientific farming which had been a hobby of his for some time.