SClogin with iPhone problem

I have a problem with SCLogin on my site at www.cyberhorsebloodstock.com.au.

It works fine on desktops with all browsers and on iPads.

When I try to use it on an iPhone the buttons do not work and won't open the modal.

If I change the module position to one lower down the template it works OK on the iPhone so there is some conflict between the SCLogin modal when used in the top module position.

I've looked at this for hours and I can't work out what the conflict is. Can you help?