The latest,
The builders provided written specification of materials used.
100mm cavity full filled with 100mm Knauf Ditherm 37 (0.037W/mk) mineral wool
100mm Thermalite Shield blockwork (thermal conductivity = 0.150W/mk)
Subsequently the builders have carried out an endoscopy in my presence and confirmed, that there IS cavity wall insulation installed in my property.
This house is L shaped and has six external facing wall's, one south, one west, two east and two north.
It certainly seems to me that low British Building Regulations are not adequate for all styles of house? A house built to the supposed latest UK building regulations in 2013, should not cool as rapidly as an un-insulated 1954 house like my last one. Similarly, during the recently hot weather, the house should not heat up inside so rapidly when the temperatures are high outside. I've been monitoring outside and inside temperatures with a TFA electronic outdoor/indoor thermometer. On the warmest day of the year here by 13:00 the inside outside temperatures were equal at 23c, (obviously no CH was on).
Along with other noticeable deficiencies in this newly built house e.g. extremely poor sound insulation, UK building regulations ARE today, still very poor.