Hi Eirwen
I see from your post
http://www.rootschat.com/links/04hx/ that you have the 1852 certificate and that you are wondering if the surnames were switched on the certificate?
What was the Ann “Lewis” father’s name & occupation on the marriage certificate? Have your tried finding a matching Ann Davies or Ann Lewis on earlier censuses?
The name Ann Davies was such a common one it could have been a friend or even the bride's mother. Another possibility is that Ann Lewis was a widow with maiden name Davies.
I found this couple in 1851 in Tredeger, Monmouthshire but couldn't find them again on 1861 - nothing new for me
HO107/2448/40/29
John Lewis, age 23, head, born Glamorgan
Ann Lewis, age 20, wife, born Monmouth
William Lewis, age 1yr (transcribed as 1 mth)
David Lewis, age 2 mths
Heather