[chrisridd]

So the cleanest solution seems to me to use another HTML element that doesn't match the default non-patched kepub stylesheet, and then style that to be centred. For example:

<span class="centred">***</span>
...

span.centred {
    display: block;
    text-align: center;
    /* etc */
}

Pick another element if abusing <span> offends, but you get the idea.