I appreciate AJAX isn’t supported for IE8. (Actually it doesn’t seem to work for IE9 either, but submitting the form seems OK, and that’s enough for us.)
However, submitting the form manually doesn’t always work with IE8. If you just enter a search term, that works. But as soon as you use the datepicker, it seems like the form won’t submit at all to do the search.
We have a private staging server we can give access to if I can post the details to you privately.