I am sure I could see the Outlook folders being picked up in the migration process but I can’t find them
They probably went into local folders. Make sure those local folders are showing by going to menu/tools/settings/general and in the general section, check “Show local folders”.
Thta box was already checked
It may be that Local Folders are not expanded. Click on the arrow indicator to the left of Local Folders and Inbox if present.
You could also search for a message you know should be in those folders, then by sorting the message list by Folder, you will be able to see where it is stored.
If you can’t find them at all, you can import them again by Menu > File > Import > Microsoft Outlook, and then selecting only the folders you require.