Right Sidebar not fitting on Blog Page

Hi,

This is a great and has been easy to work with. I have only had one issue:

The sidebar that is positioned on the right on the page templates, is jumping below the posts on the blog (single post) page.

For example, on these two pages it is fitting fine:
https://www.petrazikmannphysio.co.za/blog/
https://www.petrazikmannphysio.co.za/equine-physiotheraphy/

When viewing the post on it’s own, the sidebar disappears to below the post:
https://www.petrazikmannphysio.co.za/hints-tips/

I can’t see where to fix this. Have looked at it using Google’s Inspect Element but can’t seem to find the issue. Nothing I try is working.

Can anyone help here?