It's the little things :)
We had 3 kids and 3 adults. This unit was properly stocked with enough toilet paper, washer/dryer detergent & softener, dishwasher soap ect. to last us our 5 days. Very appreciated! The washer / dryer is in the unit and works great! I would have packed less knowing this, so something to keep in mind.
The cook top works great if you find yourself making a meal. A tesco is a few minutes walk away -- might want to bring a canvas tote for lugging groceries back. Comes in handy.
The bathrooms: 1 full bath and one 1/2 bath.
6 of us worked well in this unit. The bed mattresses looked thin at first glance... but we all slept really well, even my older parents. All rooms were a very nice size - never felt cramped.
This unit is in a quiet building (with a lift!) 2 blocks from Covent Garden market -- which is perfect. The unit is not on a crazy busy street. The front bedroom you should expect a bit more outside noise - there is a school next door. We used a white noise app on our phone and heard nothing!
Covent Garden is a wonderful area to explore. Shops, restaurants (both high end and very moderate) and street performers... and of course, the Underground - which we used every day. So easy! *The Underground (Piccadilly line) goes straight from Heathrow to Covent Garden.
You are a casual 10 min walk to Trafalgar Square or Piccadilly Circus. My son and I walked to the Palace one night in 20 minutes. Truly this location is wonderful. Enjoy!