The reason I asked was because I saw yourself and others on here saying it was 2 months. You are correct but I don't want to rock the boat so I'll go with what i was told.
2 years ago i had to provide a letter from the receptionist at my building to confirm i lived there despite having all the documentation I've used for 10 years as proof of address. Again, no point is arguing so I take one every year now.
I did mine online today again and got the confirmation within an hour. When it's as easy as that anyone who can do it online might as well continue to do so rather than wait to see what happens in the near future.
I always go with more paperwork than required, even taking the short lived 'Alien Information form' with me but I wasn't expecting the need for a letter from the receptionist, that threw me.