My friend, David Durie (Christ Church, 1963) is the only person I know who has made marmalade from oranges from his own trees (Oxford Today, Michaelmas 2014, p. 59). When he was Governor of Gibraltar, he lived in the official residence, the Convent, which had a lot of Seville orange trees in the  garden.

When he was less grand, his marmalade was pretty good. The marmalade he gave me as a gift, after a stay in the Convent, was outstanding!