Ooh. Ooh! This was featured on a very early Grand Designs episode. I cannot recall where in the UK it was (but possibly Lancashire???) but I remember the couple whose house it was were called Ben & Merry. Their house was like a period type cottage on a triangular plot in a village.
I remember this as the house went up PDQ as a result of the SIPS. You may need to trawl back to the 2001/2002 archives of GD to watch it though. YouTube might be a good bet.