Built the collation file using the hard-coded Unicode sequence as shown in the previous post, and tested it, but it seems to fail completely, which is a little puzzling. I'm now thinking that hard-coding the actual Unicode characters into the text, as opposed to defining them ahead of time using escapes, is probably causing the problem. In any case, I have to add extra handlers for the acute and grave variants of all the vowels, so I have to go back into the code and work on it. I've made a start, but run out of time for today.