Return an array of ID's

Have you reviewed https://codex.www.ads-software.com/Function_Reference/get_pages ?

Yes I did – but I could only seem to return the parent ID of child/grandchild posts and more specifically of that current page. Rather than just a list of all top level Page ID’s.

Have you tried setting parent to zero?

parent
(integer) List those pages that have the provided single page only ID as parent. Defaults to -1 (displays all Pages regardless of parent). Note that the ‘hierarchical’ parameter must be set to 0 (false) — which is not default — or else no results will be returned for any page other than the top level pages with no parent (ID=0) and the default all pages (ID=-1). In contrast to the ‘child_of’ parameter, this parameter only returns the direct descendants of the parent, no ‘grandchildren’. You can obviate the ‘hierarchical’ set to 0 requirement by passing a ‘child_of’ parameter set to the same (parent) ID value.

-1 – default, no parent restriction
0 – returns all top level pages

Thanks, I was getting myself a bit confused as I needed a clean array of top level page ID’s and I wasn’t getting it until I did a foreach.

So for others, this is my answer (thanks to Esmi too ??

$pageids = array();
$arrs=get_pages( array( 'parent' => 0,'post_type' => 'page', 'post_status' => 'publish' ) );
    foreach($arrs as $arr){
     $excludeparents[] = $arr->ID;
}
//print_r($excludeparents);

Glad to hear that you got this sorted. ??