SELECT actor_actress FROM table_25831483_1 WHERE last_appearance = "1 January 2010" AND total = 20 AND character = "Vanessa 'Nessa' Jenkins"
Siapakah aktor/aktris dengan penampilan terakhir 1 Januari 2010 dan total 20 dan karakter adalah Vanessa 'Nessa' Jenkins?
CREATE TABLE table_25831483_1 (actor_actress VARCHAR, character VARCHAR, last_appearance VARCHAR, total VARCHAR)