After lots of conversations and meetings with various architects we have commissioned Dyer-Grimes to do our house renovation and extensions.
We really liked their knowledge of the local area, the office which is in Putney had a nice feel plus they were very, very honest about what they could and couldn't do.
The costs were all explained thoroughly and we were very impressed by suggestions that we had never thought of before along with our options.
Yes, it takes time but if your project is a big one (which it sounds like it could be) then chat and meet as many architects as possible.
Some of the ones recommended on here sent me a 'copy and paste' email outlining their costs for a meeting which really didn't impress me.
We had two consultants with Dyer-Grimes before making our decision and not once did they try and charge us a fee.
If you would like to speak to someone I would suggest dropping John Dyer-Grimes and email
http://www.dyergrimesarchitects.com
Good luck