I have an idea I know what it means. I could be wrong but I think it's Gaelic. If I'm right, Golier is actually go leor, which means, plenty of something. "We'll sing plenty." Judging by the spelling of golier, Belloc probably heard a someone from west Cork say it. Munster Irish can sometimes flatten out broad vowels, making them sound slender. Anyway, that my two cents worth.

Dave