I can certainly recommend Hurlingham Developments over in Fulham who cover SW London.www.hurlinghamdevelopments.co.uk
. Speak to Andrew who will be able to talk about previous projects ranging from basements, lofts, double additions, pods and full refurbs. They also have their own teams and nothing is sub contracted out which means the tender will be priced competitively. Contact Andrew at Hurlingham on 07739174360.
Anyway hope that helps, if you need any pointers on architects then please feel free to contact me as I used to be an agent in SWLondon.