Hi there, we specialise in designing and project managing basements on behalf of clients, from first concept right through to handover. We have written a guide here
http://www.ensoul.co.uk/blog/posts/lond ... basements/ although it's focused on under-garden, the principles equally apply to under house. Call me if you'd like to discuss, best regards, Mike Lander, Director, Ensoul 020 3637 0700