How do you pull out second level structure entries based on their parent?
Ok I've worked this out from above and adding some other code and now it works as below:

{% set parent = entry.getAncestors().first() %}
{% for subnav in craft.entries.section('mySection').descendantOf(parent).descendantDist('1') %}
    &lt;li&gt;&lt;a href="{{ subnav.url }}"&gt;{{ subnav.title }}&lt;/a&gt;&lt;/li&gt;
{% endfor %}


Hope this assists someone else.