A prestige build - with no cavity wall insulation

We visited a property recently whereby the customer decided on the day of the snagging inspection to get us to check the cavity wall. This ended up being a good decision as her house had absolutely no insulation.
Based on the size of property, this issue will have cost her several thousands of pounds extra in heating costs every year. It goes to show that despite the volumes of documents given on handover showing tests carried out (such as air tests) they don't really actually amount to much when fundamental flaws like this go unnoticed.