Json columns not appearing

[JRowe]

Hello,

I'm adding some new data to an Import query in PowerBI. The data is in JSON format,

In PowerQuery Editor, I've right-click on the column we want to parse JSON, and selected "Transform" and "JSON"

I've "expanded" the button that appeared on the top right corner of column header. 

This has only loaded a list of 27 columns (there should be many more)

Clicking on "Load more" doesn't add any extra columns. There is a message that reads "limit of 1000 scanned rows reached" but I'm not sure how to change this or how to get the missing columns of data added.

Hope someone can help,

Kind regards,

John