Need to replace category block in admin.php?page=el_admin_new

Hello All,

I require help. I need to remove the categories box in the ‘Add New event’ page and replace it with the Author category box (from Author Category plugin) so that authors can only select from their specific categories. Below is the code to remove and replace it from a post (in author-category.php), however I cannot seem to be able to remove/add the block in “Add New Event’ page. (Version 3.8.4) when I change ‘post’ in the code below to the url of the page I get no result.
I have tried
‘admin.php?page=el_admin_new’
‘page=el_admin_new’
‘el_admin_new’

It seems to be a global function which I can add to (in author-category.php). Any help on how to achieve this would be appreciated.

remove_meta_box(‘categorydiv’, ‘post’, ‘side’);
//add user specific categories
add_meta_box(
‘author_cat’
,__( ‘Author category’,$this->txtDomain )
,array( &$this, ‘render_meta_box_content’ )
,’post’
,’side’
,’low’
);

Many Thanks,
Ivo

https://wordpress.org/plugins/event-list/