We had this a few pages back, mate. If you report as ill with the Zoe app, it asks a couple of dozen questions about your symptoms- I'm pretty sure that it then assigns a weighting based on earlier responses combined with actual test data to determine whether or not you likely have it. The guy who heads up the research team said earlier in the week that if you have the classic cold symptoms of sneezing and a runny nose, then you almost certainly don't have Covid.
The app has pretty much been spot on with trends in actual testing data and such a large increase- it was about 1600 a day not so long ago- is really bad. As for deaths, they will lag infections and hospitalisations, so it's a few weeks before you see the figures. Both deaths and hospitalisations have pretty much doubled from a couple of weeks back already though.