<div dir="ltr">Ah, I now recognise the difference I overlooked. I need \AtBeginDocument{\XeTeXmathcode...}, which I did originally have, but I managed to lose it, somehow. It appears that amsmath does something with the minus at begin document, and I can't change it before amsmath fiddles with it.<br>
<br>Times New Roman (at least my version) does in fact have the minus sign, but I just used that as an example font that everybody has, it doesn't matter which font is chosen.<br><div class="gmail_quote"><div><br>How strange this didn't make it into people's inboxes. I was going to send again if not received a reply by tomorrow.<br>
<br>Andrew<br></div></div></div>