Hi
Well the Marriage certificate will give you the following information
Ages of them both
address they lived at
Thier occupations
And both Father's and their occupations as well
also you will get 2 witness's which in a lot of cases can be family members
Details of the marriage are as follows
Marriages Jun Q 1934
Thomas Joseph Spouse Trancho Merthy T 11a Page 1496
Trancho Pura Spouse Thomas Merthy T 11a Page 1496
Angie
You can gain a lot of information and could possibly help get you onto the 1901 census and tracing backwards as their father's should obviously be around by then

PS it soon gets addictive LOL