The National Audit Office’s report considered by the Committee concluded that ECO4 and GBIS combined with the consumer protection and quality assurance system resulted in an overly complex system, with many different actors. It reported that nobody spoken to during its investigation could give a comprehensive explanation of how the system was meant to work, and that there was no central document clearly setting out how the system should operate across the different organisations and processes.66 In their written evidence submissions to us, Severn Wye Energy Agency, Fuel Poverty Action, Kingspan Insulation Ltd and UKAS identified this fragmentation and complexity as a contributing factor to the high level of faulty installations, as well as the difficulty people subsequently face in getting the defects fixed.67 UKAS described a “multi-tiered system” comprising “the accreditation; we accredit the certification bodies. 63 Qq 55, 116 64 C&AG’s Report, para 1.8 65 C&AG’s Report, para 3.5 and Figure 5 66 C&AG’s Report, para 3.8 67 FEE0003, FEE0025, FEE0010, FEE0022 19 The certification bodies then certify the installers. Those certification bodies are also TrustMark scheme providers. Then there is the installer and the retrofit co-ordinator—[ … ]” which “can work if there is a shared understanding of the mission and the risk that relates to it”.68