Hmm, yet another interesting page, thanks Calen!
But it wasn't a SID-tune, it was an Amiga PT/ST/NT- 'chiptune'.mod.
I've browsed through all the suggested pages (Thanks y'all) but still can't find it.
My only hope now is to either contact the probable composer, or go through loads of backup-disks I made some 10-12 years ago.