Merivale was educated at Rossall School, and Keble College, Oxford[2] (he graduated Bachelor of Arts {BA} in 1908 and proceeded Master of Arts (Oxford) {MA Oxon} in 1913),[1] and trained for the ministry at Cuddesdon College.

[1] Molyneux then served as Assistant Bishop of Melanesia from 1925 to 1928:[2] initially, he had responsibility for the Southern Archdeaconery (based in Lolowai, Aoba (now called Ambae), but lived primarily in the Banks Islands; however, as Steward's health declined, Molyneux increasingly assisted him throughout the diocese.

[1] Steward having announced his imminent resignation (due to ill-health), on 13 June 1928 the diocesan synod unanimously chose to nominate Molyneux for the diocesan See;[1] Steward having resigned effective 1 August,[8] the New Zealand bishops elected Molyneux on 16 August, and he was enthroned at St Luke's Cathedral, Siota on 13 November.

He arrived back in Britain in January 1932, where he retired to Hampshire — initially with his father at Martyr Worthy rectory.

Cyril Garbett, Bishop of Winchester, declined to license the younger Molyneux to any ministry;[1] he became a farmer.