My girlfriend and I enjoyed our stay in Covent Garden so very much! The location was absolutely perfect. Situated atop a posh shop on King Street, we were in walking distance to endless eateries, cute cafes and tourist destinations such a Westminster Abbey, Big Ben, the Tate museum, Millennial Bridge and more. This area is extremely pedestrian friendly bizarrely clean (in a good way) and the perfect balance between lively during the day and quiet at night.
We took the Underground from Heathrow to and from the airport which took about 50 minutes each way. The flat itself is a quick pop around the corner from Covent Garden station.
The apartment was warm, cozy and wonderful. Despite not meeting Sarah, we had absolutely no problems checking in! We did, however, experience trouble connecting to the wifi. It didn't work for us at all. Luckily, we were able to connect to a nearby wifi network, but that network was slow and not secure. We were traveling internationally, so having access to wifi was pretty important...
Overall, we had a wonderful time during our trip to London and would love to stay in this area again.