I rented a room for only 2 via the internet at Hostel Acacia. It offers cheap sleeps very close to the center, in a great location.

Yet, I was disappointed in the way the hostel is kept clean and nice. Our room was on the top floor, it was not very clean. All was old and in a pityful shape. The first liters of water that came out in the bath tube were brown.
Next time, I may pay a bit more for a room, but this is not the kind of place I wish to stay at, even with a low fare and in a nice area.

It was nearly 2 years ago, so the situation may have changed since then.

Amenities for HOSTEL ACACIA LONDON