I would estimate that at least 50% of my countrymen and women would oppose Homosexual "marriage" in a referendum
You're probably right - welcome back to the twentieth century.
For all the smugness, the U.K. remains the place with major racist and homophobic issues in these Islands

The result in Britain would be almost exactly the same. On these figures, a few percent more support for the YES side.

http://www.telegraph.co.uk/news/religion/11626678/Surge-in-support-for-gay-marriage.html

On the other hand there may, for all I know, be more anti-British bigotry in Ireland than there is anti-Irish bigotry in Britain. At least, you're doing your bit to make that the case.