If in Cuba you would be pleased that there is a British Embassy in Havana, Cuba. If you have any questions about immigration to the UK, be it a marriage visa orthen speak to the staff at the British Embassy in Havana. If you need to register a child as a British national born in Cuba or or worst then call them on the telephone number listed or go in person to speak to them during the operating hours listed below.
British Embassy of Havana, Cuba
Calle 34 no. 702 e/ 7ma y 17,