I write stories set throughout the nineteenth century, a time of flux in the details around marriage in England and Scotland. I am forever having to re-research this information, so I’m posting some research links here. This includes the all important information on Gretna Green marriages, in the final link. Based on these websites, I’m guessing it would be pretty difficult to get a special license and marry within one day.
https://familysearch.org/learn/wiki/en/Marriage_Allegations,_Bonds_and_Licences_in_England_and_Wales
http://www.songsmyth.com/weddings.html
http://en.wikipedia.org/wiki/Marriage_license