London Hotels

I stayed at the Premier Inn London Westminster, St James Park that was in a spectacular location. My sister and I shared a room with one long bed that wasn’t wide enough to sleep side by side so we slept across the length of the bed in a fetal position with lots of room in between. Good thing we’re both petite.
I wanted two beds but there was no customer service to ask before I made the booking. Other than that it was fine.

The best location depends to a considerable degree on how many nights you're spending in London and what sights you want to see. I've stayed at the County Hall location (near Waterloo) and at the Holborn location. As hotels they were both perfectly fine. County Hall wouldn't be my choice for someone not interested in Westminster Abbey, the Churchill War Rooms or the Imperial War Museum--but lots of folks do want to see at least one or two of those places. Holborn is great for folks who plan to make multiple trips to the British Museum, but it's a bit more expensive than many of the other London PIs, so perhaps not the best choice if you don't care about the British Museum and do care about your wallet.

To me the Southwark location isn't as convenient, but perhaps it would work for your particular sightseeing plans.

The best location depends on what you want to do and any early or late connections

Do note that Premier are often suggested due to their price - but they use a very aggressive algorithm that sees low prices well in advance, and rapidly growing prices. At short notice they can end up very much not value. This year some Premier rooms are listed at over £400, a long way north or where they start

MaryPat, I am looking for family rooms, and Westminster does not have family rooms.

I know that the Paddington Basin hotel has family rooms.
https://www.premierinn.com/gb/en/hotels/england/greater-london/london/london-paddington-paddington-basin.html