Im not 100% sure but i think i have found a solution/cause to this.
Yesterday i downloaded the Oswald fonts to my pc (in order to use the font within a logo), it was after this that i spotted the issues with the Oswald font messing up on firefox and chrome (internet explorer was displaying them ok). I thought i would delete the font i had installed on my pc yesterday, but windows 7 would not let me delete the fonts as they said they were being used.
I restarted the machine, then i was able to delete the font. When i now view the site (and the bikestore demo) the fonts are displaying correctly on both firefox and chrome.
So it was either the pc restart, or the deletion of the font that cured the problem.
Can anyone shed any light on this? Would having the Oswald font installed on the machine effect the font display on the website?.
Thanks