QUOTE(pianocelloflute @ Jul 20 2009, 01:22 PM)

It turned out I had done a whole piece on some relatively unknown hymn tune for one of my GCSE pieces-
until someone else pointed it out (and then it become blindingly obvious to me where the tune came form) I was doing quite well- I had written pages and pages of various ideas (not linked together) and my teacher came over to hear my work, and started singing along to it. Damn!

There is always
someone who recognises it!

My son wrote a song and was really pleased with it until his cousin pointed out to him that it had already been written by someone else!
QUOTE(mwl1 @ Jul 19 2009, 05:19 PM)

Should I go back to the drawing board?...

I would change the particular part of the Gloria, even if it's just a bit of tweaking, because you're obviously not completely happy, and if only one person said afterwards 'did you know that the first two bars....?' you would wish you had done something about it.