Vyvyan joined the British army in 1947 and served with distinction in the 2nd Battalion 6th Gurkha rifles where he was awarded the MC
He joined SAF after retirement from British Army in 1969 and served as 2 i/c MR.
In 1971, Vyvyan was appointed Askar Liaison Officer and made responsible for the
Wali of Dhofar's Baluch Askars known as the Baluch Guard.
In January 1973, the 800 strong Baluch Guard became part of SAF and re-named the Frontier Force with Vyvyan as its CO and Lt Khuda Bux Badal as the only other SAF officer.
Vyvyan commanded FF until he left SAF in November 1974.
He was 88 years of age at his death on the 2nd of February 2018