Just realised there's a missing header for the default note which is a crothcet/quarter note. I think that should be L:1/4. Perhaps that's optional but also the "X:" which I suspect is not.

Where would I find noteworthy composer, bearing in mind that this is not even my PC?

This may be a problem that I haven't considered. The two little notes at the beginning of the tune (anacrusis is, I think, the correct musical term), they don't make up a full bar. I wonder of this causes a problem.