1861 we have;
George Trcagen, 29
Harriet Trcagen, 26
Sydney Trcagen, 4
Charles Trcagen, 1
William Poore, 24
1871
George Treagus, 39
Harriett Treagus, 37
Sydney Treagus, 14
Thomas Treagus, 9
William Treagus, 4
Mary Ann Treagus, 1
So looks to me this is the right Marriage for this couple;
4 June 1855, St Andrew, West Dean
George TREAGUS , 23, Bachelor, Lanourer, Father WILLIAM, Labourer
Harriet SYLVESTER, 21, Spinster, Father ROBERT, Labourer
So are there more than one couple named George/Harriett Treagus around?