As far as five-star hotels are concerned, I have never came across one that was not guest-friendly. Whether it was Landmark, Sherton or Marriot, there were no problems at any of them. Unfortunately, I can't say anything definitive about the Oriental 🙁. In my opinion, the Landmark is one star class higher than the Adelphi. Especially if you get a special offer at the Landmark, which are offered from time to time, i would prefer it hands down.