I presume your interest lies in the mrge of Frederick George Codd to Dorothy M. Jones in 1937 in one of the many parish churches, chapels or registry offices covered by the Haverfordwest registration district.
The birth of Frederick was done in the Haverfordwest registration district in 1911 and that of Dorothy (May) Jones was done in the Pembroke registration district in 1910.
Given the fathers name and the mothers maiden name from either birth certificate and I can probably assist your research further back (if required).
Since it is some two years on since your posting you are probably way past the point by now anyway.
Rgds
Orielbenfro