London Premier Inn

Premier Inn at County Hall.

Not going say it’s the best but definitely fits your criteria.

What do you need from a “gathering space”? Would the breakfast room do?

For context there are well over 100 Premier Inns in London and 272 Tube stations so you are likely to be close to a tube station. I would suggest County Hall, Ealing Broadway, Holborn for starters.

With the exception of a few in the outlying areas, almost all PIs are within 2-10 minutes walking to a tube or train station. All have a breakfast room or restaurant on-site or next door. All have AC. As for a "gathering space" for a dozen people- is this for impromptu, informal chats or daily scheduled meetings? As mentioned, the breakfast room may be available during off hours. Most PIs I've been to have small lobbies, so not likely suitable, but a few have actual meeting rooms for business meetings. IMO there is no "best". Frequently recommended here are Waterloo, County Hall, and Holborn. I prefer Kings Cross or St Pancras as we often use the train stations there, and there are multiple tube lines available.

County Hall is a good one, and newer than some of the others and also larger, so it might work well for you. As the others have said, there's no real gathering space except the breakfast room, which I think you can use during the day. I've gone in there before and gotten a cup of coffee.

They have air conditioning, and also, as noted, breakfast is available but is not included in the price. You have a choice of a continental breakfast or a cooked breakfast for a slightly larger cost. Also, if you pay a little extra for a premium plus room, you will get a mini fridge, a Nespresso machine, a slightly larger room and premium wifi. Depending on the price, that may or may not be worth it.

I liked County Hall because there was a Gail's Bakery just a block or so away, which is great for take-away breakfasts, lunch, and dinner. There's also an M&S food hall close by where you can buy groceries for your room and snacks to have in the evening. There are many restaurants nearby. You can walk most any place to get to the main sites, like Westminster Abbey, the Globe, and so on. The Westminster Tube station is just a quick walk over the Westminster Bridge, and Waterloo station is about a fifteen-minute walk from the hotel. I even walked to the London Theatre area near Covent Garden one evening. It was about a mile away, but it was a beautiful walk and the lights were out all over London. I wouldn't hesitate to do it again.

Premier Inn St Pancras ticks all your boxes, also.

What type of "gathering space"? When we travel with others in the UK, we sometimes choose a nearby pub as our rendezvous spot.

BTW, Premier Inn breakfasts can be hit or miss.

I've stayed in quite a few Premier Inns in England and Scotland since 2017, of which three were in London and one at Heathrow. All the places I stayed were air-conditioned; verified that before booking. I'm confident the majority of PI rooms are air conditioned, but I'm nearly certain some are not, so I urge you to verify the presence of a/c.

Premier Inn rooms are fairly compact, but they are well-priced for what you get, especially during air-conditioning season when quite a lot of London's budget hotels become undesirable (at least to me) for lack of a/c. However, you do not get fancy public spaces at the PIs I've stayed in. I'm not sure there's always a chair in the lobby. I've never had breakfast at a PI, so I've never seen the inside of a PI breakfast room. Those are also used for dinner at some locations. I wouldn't assume the breakfast room would remain unlocked and accessible throughout the day and evening. I'd inquire at the specific PI I was considering. That will probably be somewhat difficult to do, because PI phones are not usually answered by a human being, and email addresses for individual hotels are not on the website. The trick is to book a room (refundable, of course) and look for the specific hotel's email address in the confirmation message. They seem to answer emails sent to those addresses.

Of the two hotels located near Waterloo Station, I have a significant preference for County Hall over Waterloo. Waterloo isn't bad, but responsiveness to guest requests (extra towels, etc.) wasn't as good there, and the Wi-Fi really wasn't usable in our room, even after they gave us the code for premium Wi-Fi. In three stays at County Hall, I haven't run into either issue. I realize Wi-Fi quality can vary from room to room, but the Waterloo PI should have been able to solve the problem in our room with some additional hardware. For sure we weren't the first to complain, they were way too ready to give us the premium-WiFi code for free to believe it was a sudden problem.