Liquid Collections: Accessing webapp fields with names that include spaces, inside attribute values

(Answered the question as I was writing it...)

What is the syntax for accessing webapp fields such as "Customer Surname", when using Liquid Collections?

The old syntax allowed syntax like {tag_Customer Surname}, but I can't seem to find the equivalent for Liquid.

{module_webapps id="Customers" filter="all" collection="customers" template=""}

{% for person in this.customers %}

    <div class="fancydiv-{{ person['Icon Class'] }}">

        <h2>{{ person["Customer Name"] }}</h2>

    </div>

{% endfor %}

The key is to use single-quotes...