"The analysis of COVID-19, influenza and pneumonia deaths in this bulletin focuses on deaths where these conditions were the underlying cause of death (deaths “due to”), rather than deaths where the conditions were either the underlying cause or mentioned as a contributing factor (deaths “involving”). Data for deaths where COVID-19, influenza and pneumonia were a contributing factor are available in the accompanying dataset."

They also point to this document for more details: https://www.ons.gov.uk/peoplepopulationandcommunity/birthsde...

There is no way to know if somebody would have died from the flu/pneumonia if they didn't first die from COVID-19. Excess death calculations provide a hint but are confounded by additional variables created by the lockdown (eg people not getting exercise, not getting checkups, not eating as well, depression, etc.)

Furthermore excess death calculations can only take into account < one year of data at present. We don't know if it takes off 0.5, 1, 2, 3 or more years of your life expectancy ie. would you likely have died of a respiratory illness in 2021, 2022, etc. - these are important questions, I've seen estimates saying 8 years - which is a very compelling argument for lockdown - but would 0.5 or 1 year have the same gravity?