Are you building a home or homes? Are you creating a separate dwelling or dwellings? If so, you will be needing to submit a notice to Building Control which includes an energy rating (SAP calculation). In addition, you going to require an Energy Performance Certificate (EPC) from an accredited On Construction Energy Assessor.
As an accredited On Construction Energy Assessor, Walton Consultancy UK Ltd can provide this energy rating (SAP rating) and the required EPC, in some cases within 48 hours.