[elpres]

The problem is that your site is served through HTTPS, but the MathJax code is loaded via HTTP, and Chrome/Firefox refuse to load external JavaScript due to mixed content policy. The embedded images also produce a mixed content warning, but are still loaded because they are not a security risk.

[ColinWright]

Thanks ... So the link without the https should work, I'll get to fixing the proper site when I can back to my desk.

Cheers.

Edit: temporary fix in place - working on the rest of the site now 8-(