This now seems to have been resolved as i can now send from my primary email address on the iPhone and iPad
Ant-Cleall
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I have a similar issue, created two email addresses on my domain, on the Mac I can send from either of them, but on my iPhone and iPad only one of them exists. Incoming emails land OK, but I cannot reply or create new emails from the main account as its not in the drop down and when I create new the from field is blank.