The way experts count the actual toll of a pandemic is excess mortality.
Every verified data source puts it much higher than in previous years:
An additional 104,520 people have died since March 2020 across the UK. Since the onset of the pandemic there have been six deaths for every five people who would be expected to die in an average year.
Excess deaths are fatalities above the five-year average and are seen as the gold standard in interpreting how many people have died as a result of the pandemic.
UK's excess death toll since start of Covid pandemic passes 100,000
Comparing that to the recorded
96,000 COVID deaths in the UK to around that time and the figures are similar enough to match.
Wondering whether or not some (and it would be a very small percentage) of recorded Covid deaths in the UK were classified incorrectly does not invalidate the health response to the pandemic.