If you use this link, it brings up the full history for the P&O website.
https://web.archive.org/web/20210227134511/https://www.pocruises.com/
At the top right of the screen you should see this 'bar chart' , which shows the years and frequency snapshots have been taken of the website. Use this to select the year you want to look at. As you mouse over, you should see the highlighted year/month change.