The ‘menu’ is just the ul of links, will always be inside a ‘nav’
<ul class="c-menu__list c-menu--site">
<li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">A single link</a></li>
<li class="c-menu__item c-menu__item--has-children" aria-haspopup="true">
<a href="https://www.sciencemuseumgroup.org.uk/">Another link</a>
<button aria-expanded="false" class="c-menu__toggle">
<span class="screen-readers">Expand child
menu</span>
</button>
<ul class="c-menu__submenu" aria-expanded="false">
<li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">A child link with a long title that wraps</a></li>
<li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">Another child link</a></li>
<li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">Another child link</a></li>
</ul>
</li>
<li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">A single link</a></li>
</ul>
<ul class="c-menu__list {{class}}">
{{#each items}}
{{#if items}}
<li class="c-menu__item c-menu__item--has-children" aria-haspopup="true">
<a href="{{url}}">{{name}}</a>
<button aria-expanded="false" class="c-menu__toggle">
<span class="screen-readers">Expand child
menu</span>
</button>
<ul class="c-menu__submenu" aria-expanded="false">
{{#each items}}
<li class="c-menu__item"><a href="{{url}}">{{name}}</a></li>
{{/each}}
</ul>
</li>
{{else}}
<li class="c-menu__item"><a href="{{url}}" {{#if current}}aria-current="true" {{/if}}>{{name}}</a></li>
{{/if}}
{{/each}}
</ul>