Rose had to do this. Despite already living in the UK as Spouse when the rule came into force. We had to take time out of our holiday to visit the CFO session in Manila. Terrible organisation outside trying to get a 'slot' in the sessions too - but it turned out to be mostly OFWs heading to the US (a different session, maybe they teach them how to handle a gun in that session). There was a separate session for the few of the hundreds trying to get in at once (Philippine style queue) for UK/Italy on that specific day. Unless things have changed you should get there early - i.e. the night before to claim a place in the queue that becomes a scramble to get a slot in the next day's session.

I think it is only for those pre-ILR, not with ILR. Of course once you have a UK passport it won't be an issue.