ooo hello!! I was there Last Wednesday!!
ps... what I wish I had known is it says NO PHONES but people had brought phones and they just had a little cubby to put stuff in at security and gave you a number.
I was just there yesterday and I second this. Husband and I stayed at a Travelodge and took the tube from Stanmore to Bond street, and I was soooo stressed knowing that we 'couldn't' bring mobile phones, and what if something happened.....I was really irritated knowing that even though it says that no phones were allowed but you can just check them in....
When I went in the morning the citizen line wasn't very long - like 2 people ahead of us. DONT stand in the long line that you first see... the citizen line isn't very obvious and I asked a guard and he told me where I should be. We were there about an hour early and they let us in. Like someone else said...I don't think they are that strict when it comes to appointment times.
BUT: be warned....it took us 3 hours from start to finish. I think it was a total of 3 times we were called up, first to go through the paperwork, second to check something on our paperwork, and third to talk to the officer who asks you questions. So bring a book or something to do, even bring some snacks. We didn't think they would allow anything in, I felt really stupid when I saw everyone else there with prams etc and I just had two diapers and a handful of baby wipes in my purse...even forgot a bottle!! Thank god he didn't cry at all, was really lucky!
Good luck with your trip!