Many thanks for that reference, Kevin. 
I cannot see that I can post anscreen capture of a test page I just made, so I will try to show it here with a copy of teh code from that page. :
	Quote:
	
	
		| <p class="Basic-Paragraph">Pāḷi Characters</p> 
 <p class="Basic-Paragraph">ā ḍ ī ḷ ṃ ṅ ñ ṇ ṭ ū</p>
 
 <p class="Basic-Paragraph">Ā Ḍ Ī Ḷ Ṃ Ṅ Ñ Ṇ Ṭ Ū</p>
 
 <p class="Basic-Paragraph">GarNo8BPS</p>
 
 <p class="Basic-Paragraph">á ð ì ÿ í ò ó þ ú</p>
 
 <p class="Basic-Paragraph">Á Ð Ì Ÿ Í Ò Ó Þ Ú</p>
 
 | 
	
 When this test page was exported to epub, the ā character in the non-unicode font Gar8BPS came through as  á which has unicode 00E1, I want to change it to the correct ā which has unicode 0101
I can do with a Grep (regex) search in InDesign by looking for \x{00E1} and replacing it with \x{0101} 
But when I try to do the same in Find/Replace in Sigil with Regex option turned on, it does not find the á character on that page. 
I wonder what I am doing wrong in this instance?