You don't say what you may have done this already:
Go to www.freebmd.org.uk
Click on search.
Complete the search from for the marriage.This should find the marriage OK.Now click on the link which says ""Click here to learn what to do now."Part way down down the page to which that link takes you is a link which says "For current information on fees and current ordering procedures click here."That link will take you through to a GRO (General Register Office) page.Keep following the links through the GRO site and you will be able to order a copy of the marriage certificate at a cost of £7.
Repeat this for the birth of the child.As far as I can see the birth you need is the one in Ecclesfield Bierlow in the Sep quarter of 1903.
That process should provide you with all the information the public record contains about the events.
Note that the GRO is the office which holds this information.The process outlined allows you to buy the certificates direct from them.There are other sites which will order certificates from the GRO for you.Using such sites may cost you more for no better service.