Hi Chris,
Thanks for your update.
You mentioned "I don't understand how this would/should stop meeting requests not appearing in the inbox for approval however?" I would like to make some explanation about it:
If we grant the delegate access permission to someone else and select "send meeting requests to my delegates only", the meeting request will be sent to the delegates directly and the original user will not receive this notification in the inbox. Once any delegate accepts this meeting request, the meeting will show up in the original user's calendar without any notification.
For more information, you can view the following article:
Allow someone else to manage your mail and calendar (Outlook 2010)
As I know it, there are two methods for this original user to receive the meeting notifications:
1. Select "send meeting requests to my delegates and me" when adding delegates.
Or
2. Remove these delegates from the list referring to the steps above.
If you have anything unclear, please feel free to let me know and I will be glad to assist you.
Thanks,
Chris Ni