After the ceremony ended the King and Queen left for Buckingham Palace in the Gold State Coach.

Source: https://www.manchestereveningnews.co.uk/news/uk-news/gallery/coronation-king-charles-iii-queen-26858215

Charles and Camilla travel in the Gold State Coach, completed in 1762 and used at every coronation since that of William IV in 1831.

Source: https://www.huffpost.com/entry/kate-middleton-king-charles-coronation_n_64557bf7e4b00eb7e63b993d

More than 4,000 ceremonial troops are taking part in the procession, escorting the King and Queen back to Buckingham Palace in the Gold State Coach.

Source: https://leadership.ng/soldiers-faint-during-king-charles-coronation/

Queen Camilla in the Gold State Coach leaving Westminster Abbey.

Source: https://www.dailymail.co.uk/femail/article-12051779/The-biggest-diamond-world-starring-Coronation-King-Charles-Queen-Camilla.html?ns_mchannel=rss&ns_campaign=1490&ito=1490

The group planned for the protest to be visible when the newly crowned King and Queen Camilla passed through Trafalgar Square on their way from Westminster Abbey back to Buckingham Palace in the Gold State Coach.

Source: https://www.birminghammail.co.uk/news/uk-news/anti-monarchy-coronation-arrests-reported-26857699