Social icons and other icons displaying incorrectly bug

Hi,

The Highend template social icons I’m using in the top bar are displaying as blank squares, and some other icons across the site (including the footer) are displaying as Chinese characters and also rainclouds (!?). On http://www.minervatutors.com and http://www.minervatutors.co.uk.

Is there a simple and quick way to fix this?

Many thanks

Hugo