The optimization process and recommendations:

1. Avoid Correlated Subqueries (query line: 33): A correlated subquery is a subquery that contains a reference (column: country_id) to a table that also appears in the outer query. Usually correlated queries can be rewritten with a join clause, which is the best practice. The database optimizer handles joins much better than correlated subqueries. Therefore, rephrasing the query with a join will allow the optimizer to use the most efficient execution plan for the query.
2. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.

Optimal indexes for this query:

ALTER TABLE `catcontents` ADD INDEX `catcontents_idx_category_id` (`category_id`);
ALTER TABLE `content` ADD INDEX `content_idx_content_id` (`content_id`);
ALTER TABLE `countries` ADD INDEX `countries_idx_country_id` (`country_id`);
ALTER TABLE `weblinks` ADD INDEX `weblinks_idx_content_id_weblink_or_weblink_id` (`content_id`,`weblink_ordering`,`weblink_id`);
ALTER TABLE `weblinks` ADD INDEX `weblinks_idx_weblink_orderin_weblink_id` (`weblink_ordering`,`weblink_id`);

The optimized query:

SELECT
        c.content_name,
        c.content_telephone,
        c.content_address1(SELECT
            w.weblink_url 
        FROM
            weblinks w 
        WHERE
            w.content_id = c.content_id 
        ORDER BY
            w.weblink_ordering,
            w.weblink_id ASC LIMIT 1) AS content_url,
        (SELECT
            country_name 
        FROM
            countries 
        WHERE
            countries.country_id = c.country_id LIMIT 1) AS country_name,
        (SELECT
            country_iso 
        FROM
            countries 
        WHERE
            countries.country_id = c.country_id LIMIT 1) AS country_iso 
    FROM
        catcontents cc 
    LEFT JOIN
        content c 
            ON c.content_id = cc.content_id 
    WHERE
        cc.category_id = 7 
        AND (
            SELECT
                country_iso 
            FROM
                countries 
            WHERE
                countries.country_id = c.country_id LIMIT 1
        ) = 'uk' 
    ORDER BY
        cc.catcontent_ordering ASC,
        c.content_name ASC