Thanks, I've read misinformation on this in the past regarding use of the 800k for hospital bills invalidating the current extension, but looks like this is not the case.
One other situation where proof of financials is needed is mid-year transfer of stamps to new passport, not sure if this is a new requirement.
Also, does the Non O have to be cancelled at immigration - I've read mention about people making appointment for cancelling the O and getting the new PE stamp affixed on the same day?