Welcome to OSM and thanks for adding your London showroom details, although your edit didn't seem to go as intended - you ended up with the London information on the Swansea location and also on a residential area around the London showroom.  
I've reset the Swansea information and added a node in London which you can check/update as necessary:
https://www.openstreetmap.org/node/4989144188/history
https://www.openstreetmap.org/node/11042617097/history
Cebderby (Clive)