@Tod ********
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.