In 1851, Fox travelled to London on behalf of a group of Wellington settlers. There he met Edward Gibbon Wakefield, elder brother of William and Arthur. He discussed his ideas about a constitution for New Zealand, strongly supporting self-rule, provincial autonomy, and two elected houses of parliament. He also attempted to meet Earl Grey, the British minister for colonial possessions, but was refused. When a constitution was promulgated the following year it incorporated some of Fox's ideas, but was not satisfactory to him. Before returning to New Zealand, Fox and his wife spent some time travelling in Canada, the United States and Cuba.

Havana Bay was painted on that trip and shows a highly detailed view of Havana Bay with the Morro Castle, a picturesque fortress guarding the entrance to the bay. The watercolour has the following inscriptions in Fox's hand at the bottom of the painting:

Artillery Barracks 1853, Punto Fort, Gulf of Mexico, Moro (sic) Castle