Custom plugin capability issue

Hi All

I hope you can help.

I’ve created a plugin but I’m having problems with a capability.

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The admin page is created from

add_action('admin_menu', 'todays_orders_page'); 

function todays_orders_page() {
	add_menu_page('Todays orders', 'Todays orders', 'todays_orders', __FILE__,'todays_orders');
}

In the database for a user I have
a:1:{s:5:"todays_orders";b:1;}

Which I’m assuming is set correctly.
Using various plugins, the role I have created as “Owner” is showing as having the todays_orders activated.

I have created other admin plugins but they have always been on the main site and not on a sub site of the multisite setup. Is this a possible issue?

Any help would be much appreciated
Mark.