@Barry *******
You aren’t on a Non O visa. You’re on an extension of stay (off the back of the initial Non O visa).
Come getting a new extension you can change the reason for that extension if you meet the requirements to do so.
Go in a few weeks before it’s due with your wife and get a list of all the requirements your office will need to switch over to reason based on marriage.
As an aside there’s many on here that will suggest that you just keep doing retirement extensions as they are generally less hassle and not dependent on your wife being there at the time. There is less money to hold though so it depends on your preferences.