Ah HA! That fixed it, thank you.

Now I'm trying to add to it to make it use the Adobe Centaur font (which is nicer) if the user has that installed, and use the free webfont if not. I've set the hosted version to chmod 000 so that I can see what I'm doing, and I'm trying out src: local statements in the css file. And it only works in Chrome, not Firefox. Does firefox not pay attention to src:local or something?

I've got rid of the IE-fixing stuff for now for simplicity, and the css I'm trying is:

@font-face {
    font-family: 'Centaur';
    src: local('Centaur'), local('Centaur Regular'),
         url('http://www.firecloud.org.uk/07509_centaur-webfont.woff') format('woff'),
         url('http://www.firecloud.org.uk/07509_centaur-webfont.ttf') format('truetype'),
         url('http://www.firecloud.org.uk/07509_centaur-webfont.svg#centaurregular') format('svg');
    font-weight: normal;
    font-style: normal;

}

EDIT: But now it's working... I suspect there is some caching going on here and confusing things, either by the browsers or by DW's cssproxy. Ah well, it seems to work for now...