Everyone has a unique NHS number and has done for years. I even know mine off by heart because I moved house recently and it makes things like changing doctor and dentist easier if you know it. Now I know the government's Excel skills are pretty shocking as we saw late last year, but seriously all they have to do is start a new table in their existing databases listing NHS number, date and make of first covid vaccine, date and make of second covid vaccine. When you see how much data, photos etc the GP or hospital already store on you, adding a couple of simple vaccination dates should be simple. They do not need a fecking dedicated app, with all the conspiracy baggage it comes with, to keep track of simple stuff like this.