ah apologies, the file is box.navigation.php (tech support told me main.php)
Thank you for your help so far,
so I have this but it is not creating the sticky menu, do i need to populate data-topbar=""
<div class="sticky"><nav class="top-bar category-nav" data-topbar="" id="box-navigation" data-options="sticky_on: medium,large">
<ul class="title-area">
<li class="name"></li>
<li class="toggle-topbar left"><a href="">{$LANG.navigation.title} <svg class="icon"><use xlink:href="#icon-caret-down"></use></svg></a></li>
</ul>
<section class="top-bar-section">
<h5 class="hide">{$LANG.navigation.title}</h5>
<ul class="left">
<li class="show-for-medium-up"><a href="{$ROOT_PATH}" title="{$LANG.common.home}"><svg class="icon"><use xlink:href="#icon-home"></use></svg></a></li>
{$NAVIGATION_TREE}
{if $CTRL_CERTIFICATES && !$CATALOGUE_MODE}
<li><a href="{$URL.certificates}" title="{$LANG.navigation.giftcerts}">{$LANG.navigation.giftcerts}</a></li>
{/if}
{if $CTRL_SALE}
<li><a href="{$URL.saleitems}" title="{$LANG.navigation.saleitems}">{$LANG.navigation.saleitems}</a></li>
{/if}
</ul>
</section>
</nav></div>