I think this might be Dennis's marriage
Marriages Jun 1904
Fitzgerald Dennis Newport, M. 11a 429
Tucker Fanny Newport, M. 11a 429
Living here in 1911
9 Bright St Cross Keys Mon, Risca, Monmouthshire
His birthplace has been put down as Cardiff, Glam. but if you try and find a birth for Cardiff the only two that come up in the relevant time frame are:-
FITZGERALD, DENNIS WHELAN
GRO Reference: 1882 M Quarter in LIVERPOOL Volume 08B Page 8
FITZGERALD, DENNIS HARDING
GRO Reference: 1884 J Quarter in POPLAR Volume 01C Page 719