The Marble Arch Hotel by Thistle

You'd expect a hotel bar on Bryanston Street to be all beige corporate blandness and overpriced G&Ts for jet-lagged Americans. Instead, you'll find yourself in a space that actually understands what makes a proper bar tick. The cocktail list isn't trying to reinvent the wheel, but they're made with care and the kind of attention you'd hope for but rarely get in this part of Marylebone. The fact it's open around the clock is genuinely useful when you're stumbling back from somewhere in Fitzrovia at an ungodly hour and need one more. Yes, you're paying hotel prices, but the setting feels more grown-up pub than sterile lobby, and the staff seem to actually enjoy what they're doing rather than just going through the motions.