Custom query return

Okay i’m going to try to add this as an answer because I can’t do codes in comments:

<?php
if($_GET['colour'] && !empty ($_GET['colour']))
{
$colours= $_GET['colour'];  //notice i pluralized.
}
?>  //your code ended php, so i assume there is something here as it is not started again.


$meta_query = array('relation' => 'OR');
foreach ($colours as $colour) {
    $meta_query[] = array(
        'key'       => 'colour',
        'value'     => $colour, //not sure why you have parentheses, but try with and without here i guess
        'compare'   => 'like',  //switched back out of in because we are out of the array
    );
}