The data I referred to below is just from hospitals, and there are various reasons for death numbers coming out over time.
For one, the reporting systems used are not designed to report deaths like this on a daily basis. It's a manual process, which doesn't always happen for each hospital trust every day, and quite often not at weekends. Hence numbers for Sunday and Monday (reported by trusts on Sat and Sun) are often super low.
Secondly, deaths aren't reported without a positive test, which sometimes comes in after death.
There is also sometimes an issue in reporting between a care home and a hospital, which can led to delays or double counting, if say a resident is transferred between settings and dies quickly afterwards.
Basically, we don't have a system that is set up to report deaths so quickly; normally we wait for the death certificate, which can take up to 5 days. Now we are demanding daily data, and the system just can't do that reliably. Care home deaths suffer from the same delay issues.
Hence why data gets revised constantly, and the " daily deaths" are actually "deaths that happened mostly over the last week, sometimes a bit older"!