Startup Growth Lite - How To Set Width For Content Type
Typical, minutes after posting the question I finally found the answer. 

What has worked for me was adding my content type to the template.php file startupgrowth_lite_preprocess_page function, our content type was called 'client_work' which once added set it to display the same as the 'page' content type.

I added the following

&amp;&amp; $variables['node']-&gt;type != 'client_work'


to the end of the first if statement in the function below (around line 494).

function startupgrowth_lite_preprocess_page(&amp;$variables) {

    /**
     * Insert variables into the page template.
     */
    if (isset($variables['node']) &amp;&amp; $variables['node']-&gt;type != 'page' &amp;&amp; $variables['node']-&gt;type != 'client_work') {