1.23 Parallax Frame update – Header Image issue

Hi there, have just updated to 1.23 and everything seems to be working fine, except for the fact that my header image seems to scale massively...unless the browser window is narrowed enough to hide the right column at which point it acts correctly/as it used to before the update. http://www.simonphipps.com/ I have checked plug-ins and tried with and without custom CSS, no obvious conflicts. Seems to be that the header image is being scaled to the full height of the screen, so that by default my home page shows a blurry version of the top of my head... Any suggestions? Thanks