The UK Government does not include in its daily toll the death of anyone who tested positive for COVID-19, but whose test was carried out by one of the Government's commercial partners.
In other words, "pillar 2" deaths aren't being reported.
coronavirus.data.gov.uk/about
But only 180,202 people from the pillar 1 contingent have tested positive to date. So the 36,393 deaths reported to date come from those 180,202 people (20.2%)
The other 73,993 positives? Who knows!