Dopo l’Unità d’Italia, sembra che abbia trovato una clientela inglese, come il suo maestro, Alessandro Castelli. Iniziò a esporre in Gran Bretagna nel 1862. Nel 1864, venne coinvolto in uno scandalo amoroso riguardante una giovane donna inglese a Roma. 

After the Unity of Italy, it seems that the artist found a clientele in Great Britain, as did his master, Alessandro Castelli. He began exhibiting in Great Britain in 1862. In 1864, he was involved in a romantic scandal regarding a young Englishwoman in Rome.

Dublino (1865), Londra (1862, 1868, 1869, 1871, 1873, 1874)

s.a., International Exhibition. Pictures of Various Nations, in “The Art Journal”, 1 ottobre 1871, p. 241.

s.a., Art Notes, in “The Magazine of Art”, vol. IV, 1881 (ottobre 1880), p. ii.

A. Graves, A Dictionary of Artists who have exhibited Works at the Principal London Exhibitions from 1870 to 1893, Londra 1901 (ristampa 1973), ad vocem (Cumbo e Borgia).

A. Graves, The Royal Academy of Arts. A complete dictionary of contributors and their work from its foundation in 1769 to 1904, Londra 1905, vol. II (ristampa 1970), ad vocem (Cumbo e Borgia).

https://www.britishnewspaperarchive.co.uk/search/results?basicsearch=ettore%20cumbo%20borgia&retrievecountrycounts=false