This is a modern style eath design using taditional cob construction. with a green roof.
The earth walls could easaly have been rammed earth, adobi clay lump or any of a wide range of earth construction.
Samples of earth were sent to Bath University and were laboritory tested for strength the result was very good reaching just over 1kN/mm2.
Getting earth construction to comply with Approvred Document part L is acheivable as earth construction has many advantages, though some horse trading may be nesesary by designing sertain elements beyond Regulation requirments