I've not come across 'by certificate' before Rob.
But this previous post on Rootschat explains it.
It is the equivalent of Banns, so no licence to try and find by the look of it.
https://www.rootschat.com/forum/index.php?topic=696493.0From what you've written, it looks as though the 2 witnesses were part of the groom's family - well, at least there are no 'Evans' witnesses to see if they can be tied in with the bride. That's a pity.
So it looks like she added a couple of years on to her age at the marriage? Possibly because the groom was quite a bit older than her. Or the age on the Census might be out. Have you found her actual birth date?
If I read your post correctly, the address for Anne Evans given on the marriage certificate in 1892, is the same address where she, and the father Ebenezer, live in the 1891 Census?
Anne Evans must be a pretty common name in Wales, but Ebenezer not so much.
I would think it must be the same people.
Does it not give Ebenezer's profession on the marriage certificate?
Does it match with his profession on the 1891 Census?
For future reference, if you need to post an image again, as you have found, the maximum size you can post on here is 500kb.
That often means you have to reduce the size of your file.
I usually do this through the photo software on my computer (iphoto on Mac. Not sure on Microsoft).
If you load the image into the photo software, you can then re-save it as a lesser file size. Bit of trial and error to get the image as near to 500 kb as possible. This helps when then trying to read at it after it has been posted on here, as if it's a very small file, when you zoom in on it, it goes all fuzzy and pixelates.
There has to be a help page for this here on Rootschat. I'll see if I can find it.
Added:
https://www.rootschat.com/forum/index.php/topic,130922.0.htmlHow to post an image here on Rootschat.