As a rower, he was a six-time Australian national champion, raced in nine King's Cup eights for Victoria over a 15-year period, and competed at three Olympic Games.
[2] Following the 1960 King's Cup win by Western Australia and the whole selection of that crew as the Australian eight for the 1960 Rome Olympics, test races were held in Victoria and New South Wales for the other boats.
The coxed pair was graded as the fifth priority boat and Guest and his King's Cup crew-mate Neville Howell prevailed in a selection trial in Ballarat.
They had to finance their own travel to the Rome Olympics, where as a coxed pair with Ian Johnston on the rudder, they placed fourth in both their heat and repêchage.
The Australian squad took a new Sargent & Burton eight with them to the Olympics but quickly saw that its design and technology was way behind the European built Donoratico and Stampfli shells being used by the other nations.
The Victorian King's Cup crew of 1966 were selected as the Australian eight and with Guest again seated at five they rowed to a tenth placing in Bled.
[2] In the course of the semi-final, when leading the field a short distance from the finish, Ramage suffered acute oxygen loss from the high-altitude venue and they were overrun on the line.
For the 1970 World Rowing Championships in St Catharines the Vic King's Cup eight provided the stern four and the three-seated Kerry Jelbart.
At his retirement the Chief Justice of the Family Court Diana Bryant was quoted as saying "[Guest] had brought the dedication and determination typical of an elite athlete to his work" and in reference to his 're Patrick' ruling, she said that his "sympathetic call for legislative reform to assist homo-nuclear families earned him respect in the gay community and showed him to be a modern thinker ahead of his time".
[11] On his retirement from the bench in 2008 he joined the board of the Lasallian Foundation, a human rights organisation that assists the development of impoverished communities in the Asia Pacific region.