In 1921 his father retired from the ICS on account of increasing deafness[3] and the family returned to Britain.

[4] After Indian Independence Act 1947 in 1947 Peter Gwynn opted to stay on in the civil service under the new Government of India.

[5][2] In addition to his official duties Peter Gwynn contributed in his spare time to the cultural life of Andhra Pradesh, helping to found the Telugu Academy in Hyderabad and serving as a member of the governing body of the Salar Jung Museum.

[4] In 1968 the family moved to England where Peter Gwynn entered the UK civil service as a Treasury under secretary, remaining in post until his final retirement in 1976.

During his retirement he worked on his linguistic projects, compiling a Telugu grammar book in conjunction with Professor Bhadriraju Krishnamurti (A Grammar of Modern Telugu, Oxford University Press, 1985) and completing a dictionary of the Telugu language (A Telugu-English Dictionary, Oxford University Press, 1991).