Appointment was 12 o clock. Queued outside at 11am and got let straight through security in 5 minutes even tho immigration visas werent starting yet. Once inside we waited for about 40 minutes until they started I numbers. We went to a window and spent 10 minutes handing over paperwork and taking fingerprints. Guy was really nice and friendly although he almost charged me again for the visas even though I'd paid lol. Sat back down for another 10 minutes and then went and had a 10 minute chat with another really friendly woman who then said "Congratulations you're all approved. Time to book your flights." Felt like just having a chat with a co worked telling them what my plans were. Asked what my fiancee did, what I did, how old her daughter was, how we met and if we'd booked the wedding. Said our plans sounded lovely. All in all was very straight forward and easy. Best advice is just be yourself. Act natural (unless yourself and natural is an ***hole) and just talk about your love as you would to anyone else. They're there to help you and as long as you're genuine and have all the paperwork you're home and dry