Using Pagination with Timber Routes

After some messing around (and actually looking at the docs properly!) I have solved the problem. In my routing, I just need to add another map to handle paging with my custom routing:

Routes::map('items/browse/:field/:value', function($params) {
  $query = array(
    'post_type' => 'item',
    'meta_key' => $params['field'],
    'meta_value' => $params['value']
  );
  Routes::load('archive-item.php', $params, $query);
});


Routes::map('items/browse/:field/:value/page/:page', function($params) {
  $query = array(
    'post_type' => 'item',
    'meta_key' => $params['field'],
    'meta_value' => $params['value'],
    'paged' => $params['page']
  );
  Routes::load('archive-item.php', $params, $query);
});