Hello @simonp820 ,
That is how it is supposed to be. That short code in the post is referencing the data in the visualiser so WP knows what and where to import according to your post content.
In order to modify how the chart is displayed on the page you have to access the Page Editor as i mentioned in the previous reply. Not edit the Post.
Another option would be to modify it through Visualizer Library -> Edit -> Settings -> Chart Size & Placement. Here you have to play with the settings of “Chart Size/Layout”and “Placement” until you get the desired result.
https://ibb.co/xCfVLtB
https://ibb.co/T2Nmh9T
After you finish adjusting and you are happy with the result click “Save Chart”and visit your page.
I would still recommend the previous approach as you can directly see the chart displayed on your page and it is easier to see if you obtained your desired result.
Thank you and have a great day!