Hello,
Just to let you know, the marriage certificate will not provide a date of birth. It contains the names of the Bride & Groom their ages, their address, occupation, father's name and his occupation. Also names of witnesses plus place and date of the marriage.

The church probably has records of marriages which are usually free to view.

Copies of marriage certificates can be ordered online but there is a fee, see direct.gov.uk/gro for details.

Because the people you are researching are probably still alive I won't put details on display, but......

Just done a quick check and believe I have found the birth registration of Sandra, Pearl, Paul and Carol.

Have also found the registration of Carol Driver's marriage to Michael Monk.

Although the registration details are not required when ordering from the GRO, it removes the chance and cost of being sent the wrong certificate.

Because of the era you are searching you may need to subscribe to Ancestry.co.uk or FindMyPast.com to obtain registration details.

Free databases include FreeBMD which is very good for the period 1837 - 1920. There is also the IGI if looking for family pre 1900, most of the information is based on parish registers.

Sorry to be vague about your family but..... Carol's wedding may not be the only connection with the area.