Here are the instructions to view the history page, where you can see all the changes to the lesson content of a plan, including seeing the content of any deleted lessons.
This isn't surfaced in the UI, because if it was, it would be visible to the users. So instead, you have to enter to URL of the history page.
You need to be logged in as the user, and open the plan you want to view the history of.
Step One: Extract the Plan Id from the Plan Url.
The plan URL in the browser address bar will look something like this:
https://www.iugo.co.nz/Planning#Tab:plan,View:edit,Id:ebdd1224-ec60-4326-ae8d-a7c70171bcdc,Name:Plan%20Name
You want to look for the part after Id: and before ,Name:. In this case, it is
ebdd1224-ec60-4326-ae8d-a7c70171bcdc
Step Two: Generate the Plan History Url
The URL of the history page for that plan will be:
https://www.iugo.co.nz/Planning/Plans/History/ebdd1224-ec60-4326-ae8d-a7c70171bcdc
That is, you add the plan Id to the following base url: https://www.iugo.co.nz/Planning/Plans/History/