Mobile Nav via Plugin – How to remove the default responsive navigation?

Hi,
I am using a mobile menu plugin instead of the boldial one. How where in the themes files do I remove the Boldial responsive menu (as its not needed for me). It appears near the bottom of the page in code view? Just to help the speed of the site as I have quite a large menu.

<ul id=”mainnav” class=”ish-ph-mn-main_nav ish-nt-regular ish-ph-mn-be_resp ish-a-respnav” style=”display: none;”>

Thanks