How do I 'disable' my contextual filter (return all results) for uid=1?

Question

I have a View (content) created with a contextual filter. The contextual (Content:Country) filter uses PHP code to check custom fields:

global $user;
$user_uid = user_load($user->uid);
$mycountry = $user_uid->field_user_country['und']['0']['tid'];
return $mycountry;

The filter is [field_address_country] == [field_user_country] The contextual filter works fine.

However, I would like to 'disable' the filer for admin (uid=1) so that I can view all nodes regardless of the field_address_country value.

I have tried adding a condition to check for uid=1 but it doesn't work

global $user;
$user_uid = user_load($user->uid);
$mycountry = $user_uid->field_user_country['und']['0']['tid'];
if ($user_uid == '1') {return 'all';}
else {return $mycountry;};

Is there a method for returning all results (or disabling the filter) for admin user?