SimpleSearch doesn't work with iPads

I have a search page using SimpleSearch on my site at http://tgworkshop.me.uk/GMP3/search that fails to work properly with an iPad. It works reliably on all other the platforms we've tried. With an 'oldish' iPad, using Safari, it just returns a blank page.

I have no idea what can be the problem here and would much appreciate guidance. We are hoping to move out of development and into commercial use in the near future and this problem is a bit of a worry.