try citadines a'part hotels

OP here. Thanks to all for the input. We tried but couldn't get connecting rooms anywhere! I think the lesson is that it's hard to find connecting or family rooms at the last minute. We found a family room at the Landmark Hotel near the Marylebone train station. It sounds like it is a very spacious room and they are more than happy to accommodate 5 people. Hoping it is a good place. Thanks again to everyone who weighed in with advice.

Beds are smaller in the UK, so don't assume you can sleep together. I'm just back from the London and had an awful night trying to share with my 6 year old. For 4+ people, definitely get 2 joined rooms.

Airbnb.com has some great properties in London. Really with checking it out. If you must do a hotel, have you looked at places with a suite? Some might be big enough.

The Montana hotel. It is across the street from the Gloucester Road tube stop. Not fancy. Very good price. We stayed in the basement large family room with 4 people, you could easily do 5. Nice area -close to Royal Albert Hall, safe area. Nice English breakfast. (though served in an Indian restaurant above/or adjacent the hotel) This was maybe 8 years ago. Above all, I strongly recommend studying TripAdvisor

Even as a family of 4 we've usually ended up having to get two rooms in Europe. When we've added my mother and had 5 we definitely had 2 rooms. It's rare to have 2 queen size beds in a room in London. 2 twins is much more common then here. We usually stay at smaller B&Bs and just get two rooms. If you must have 1 room your best bet is going to be American chains.

You can review different hotel apartment options on TripAdvisor to get a feel for whether they suit your family needs.

We've handled this a number of different ways. Find a hotel that offers family suites or anytime of suite. More beds, more space. In general European hotel rooms are small and compact. We have also had some luck with 2 rooms that are joined by a door, one parent stays in one room with some of the kids, the other parent stays in the adjoining room with the rest of the family. We have also rented apartments which has been the best all around solution for us. You have a kitchen area to cook and save money on meals, sometimes there are laundry facilities so you cut down on stuff you need to bring. There is space to spread out with the family and everyone's needs. Have you looked for hotel's that are like apartments? They have the front desk and feel of a hotel but offer apartment like rooms? We've stayed in these in several European cities and been very happy with the arrangement.

Even in American chains, there is a pretty wide range of sizes, especially since many hotels in desirable areas have not been purpose built.

I had an enormous room at the sheraton park lane, a good size room at the marriotts in grosvenor square and swiss cottage. If you're just using it for sleeping and aren't too worried about a tight squeeze, it sounds like any of them, plus the marriott county hall, would be okay.

Outside the familiar, unless you're spending a lot, it will likely be a bit too cozy.

My son and I stayed in a familiar American chain hotel in Kensington and wouldn't have wanted to share the room with another person - too small. (And this is from someone who lives in a 1500 s.f. house...) I would try to get a flat if possible - airbnb is a good idea.

Have you tried airbnb.com

Hotels like in most European cities are not known for being spacious. Unless you want to stay in a familiar American chain.

We stayed in the marriot county hall in London. There were only three of us, but we had a room with two double beds and an enormous closet. It could easily have fit a rollaway. It was an upgraded room facing the river. Maybe call and ask?

Might look for an apt to rent?

London hotel rooms are really small. Like, smaller than NYC small sometimes. So it might be tough to fit five in one room.

We're planning a last minute trip to London and trying to find a hotel that can take my family of 5 (2 adults, 3 kids). Most of the websites say there is no availability for any rooms big enough for that group. Do we really need to get two separate hotel rooms? In the US, we usually stay without a problem in rooms with two double beds. Our youngest is 3 and happy to sleep with her siblings or in a crib.