The ‘menu’ is just the ul of links, will always be inside a ‘nav’

<ul class="c-menu__list c-menu--global">
    <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">About us</a></li>
    <li class="c-menu__item"><a href="https://collection.sciencemuseumgroup.org.uk/" aria-current="true">Collections</a></li>
    <li class="c-menu__item"><a href="https://www.sciencemuseumgroup.org.uk/">Learning</a></li>
    <li class="c-menu__item c-menu__item--has-children" aria-haspopup="true">
        <a href="#">Visit us</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="http://www.sciencemuseum.org.uk">Science Museum</a></li>
            <li class="c-menu__item"><a href="https://www.scienceandmediamuseum.org.uk">National Science and Media Museum</a></li>
            <li class="c-menu__item"><a href="https://www.scienceandindustrymuseum.org.uk">Science and Industry Museum</a></li>
            <li class="c-menu__item"><a href="http://www.railwaymuseum.org.uk">National Railway Museum</a></li>
            <li class="c-menu__item"><a href="https://www.locomotion.org.uk/">Locomotion</a></li>
        </ul>
    </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>