The Vitali family lived in the Island of Tenos and most of them were Sculptors.

They are known under two names.
One of the brothers and his children were known as Vitalis and the other brother and his children were known as Fytalis.

The best known are :
Vitalis George (1840-1901) Born in Ysteria, Tenos died in Alexandria, Egypt).

and the brothers Lazaros and George Fytalis also born in Tenos. Lazaros was born 1831 sand died 1907.

George Vitalis visited England and stayed in England for quite some time.
His first cousin Lazaros Fytalis also visited England at least in one occasion.
Their work in Greece is well known.

Marcos could have been the son of George Vitalis and I wouldn't be surprised if he was born in England.