Just done it. 60 days on arrival to Non O, was first extended to 3 months. Then had to apply and pay again for the 1 year extension. Four visits later, 12 months Non O retirement visa now obtained. According to the IO we are not supposed to do this, she said it should be obtained before leaving your own country.
I did suggest that all this could have been done in one visit but this fell on deaf ears.
Note:- There are advertisements at CW advising you to do the TM30 online. However, when you get there they also require it on paper.
Biggest waste of time and paper ever.