On the pro side of my list, the studio was in an excellent location, very near the tube and other amenities. The room itself was pretty well as described, though a little rougher around the edges than portrayed in the photographs. The landlords however, were kind enough to let us leave our baggage earlier than expected due to our early train, which was a great help.
On the flip side, there was no mention of the building being under renovations when we booked, which led to noisy builders working from 8am (and I was on a social holiday, so wasn't up and at them too early), also the hallway and entry were in a dirty state, with boxes and building supplies everywhere.
When we arrived, we were unceremoniously greeted by the cleaner who handed us our keys without a smile and then proceeded NOT to show us to our room. The aforementioned builders were so kind as to point the way.
The wifi came and went, which was all right as I had 4G signal, but I imagine that could be a problem for non-EU travellers.
Some little things that could be rectified easily - perhaps having some milk in the fridge and standard tea/coffee available. Also, perhaps as the shower head is only a rain shower (not pictured in the photographs), shower caps could be offered for those of us with longer, fussy hair.
Finally, the bed. The bed, as noted by others, is indeed smaller than a standard double and does not comfortably fit two people and is also worn out, sagging in the centre. Upon our departure, I stripped the bed (as I always do in airbnbs to help), I found the mattress protector soiled with some rather dubious looking stains.
All in all, the room was in a potentially lovely building (when not being renovated) and an excellent location (couldn't be much more convenient for the centre of London), but the room itself let us down and we would probably chose not to stay again due to the above reasons.