Coming from Paris on Eurostar covenant gardens vs Royal horse guard hotel

You mention Royal Horseguards along with Covent( note spelling) Gardens in order to see several sites in London.
We always stay in Kensington or Chelsea which are lovely. We use the tube and buses, or walk, very easy to get around and see everything we want..
We always have been able to walk to a variety of excellent restaurants. Make reservations for them before you leave home for your RS Tour. The choices are endless with many Indian restaurants all over the city. If you don't want to do that, write your hotels in advance and ask their Concierge to make them for you. You aren't limited in where you stay.
You have three nights which only gives you two days so you do need to make some plans to maximum your time.
Every time I visit London, I head to Westminster Abbey first, but you didn't mention it. It is a must see! #1!
Think of all the past and future services that are held there, the coronations, weddings, funerals, etc. Queen Elizabeth's funeral was held there; William and Kate's wedding too.
Churchill War Rooms are very near Westminster Abbey so combine them on the same day.
Combine the Tower of London and a Thames Boat ride. If something has to go, let it be the boat ride.
The British Museum is excellent and like most museums in London, is free to enter. You can go see one exhibit and then leave to do another must see for the day.
Visit St. Paul's; it is London's Cathedral. Charles and Diana were married there.
I will be happy to answer any questions you may have.

I would choose Covent Garden. It’s more central, you can walk to so many places and you’ll have hundreds of restaurants on your doorstep. Book in advance though because it’s always busy.

You don’t say what kind of restaurants you’re looking for but I would recommend Hawksmoor if you like steak.

Thanks amazing advice, will definitely adjust our itinerary.

I have a different view. The Royal Horseguards hotel is is great location, very near the Churchill WR Rooms and an easy walk to Westminster Abbey and Big Ben. And you are very close to Westminster Pier where you can catch the Uber boat Thames clipper to the Tower of London.

There are lots of restaurants lining the Thames pedestrian path on the south side of the river. Just cross on the Jubilee pedestrian bridge which starts right near the hotel. You get nice views of the river from the bridge. There are actually two Jubilee pedestrian bridges, one on either side of the Hungerford railway bridge.

You can add St. Paul’s or the Globe Theatre to your Tower ofLondon day, or the Borough market. On the St. Paul’s side of the river you can catch the #15 double decker red bus to Trafalgar Square, or get off at Aldwych to wander through Covent Garden.

Sasha thanks so much, now I'm really leaning towards the Royal horseguards. Such perfect descriptions of locations, the excitement is building. Love everyone's willingness to help. Thank you

Royal Horseguards hands down.

Don’t dawdle, book. Ideally located for what you desire to see.

10 minute stroll along the Thames path to Elizabeth’s Tower with the Big Ben bell.

The Sherlock Holmes Pub is close. Good pub grub.

Lovely St James Park, Birdcage Walk, Royal Horse Guard Parade and Museum and the Churchill War Rooms all within a 15 minute stroll.

From the nearby Embankment station you can take a Circle or District Line train to Tower Hill station which is across the road from the Tower of London. 15 minute ride.

Great city.

Always changing, yet always the same.

Enjoy!

The area right by covent gardens can be very busy. Especially on weekends. Noise may be an issue if the hotel is close by.

It boils down to what you want. Horseguards, probably quieter, many buses, convenient Trafalgar Square and Charing Cross one way, Westminster tube the other. Covent Garden (where???) buses, Piccadilly Underground, Northern Line Leicester Square tube, night life, touristy, loads of restaurants in a few steps.

You might prefer one or the other. Both are decent neighbourhoods.

The two are a 10 minute walk from each other. Not much to choose between in terms of location. Go with the hotel you like.