Try Michael Trentham Architects. He's done lots of houses in this area and knows the planning system well. If you PM me I will tell you about planning/ building in this area as I have lots of recent experience in doing my own house.
If you need an architect to help with planning etc, speak to Greg Lomas or Will Foster of Foster Lomas, based on Weller St. I used to go to breakfast networking with Greg, they're a good practice. We also recently did some planning related work with them.