The gov as stated are we are going to require a covid pass in crowded place from the end of Setpember, all must provide a vaccine passport (NHS app). or letter (which can be requested) to show that you have had a vaccine. Further details will issued closer the time.
Also i assume lateral flow taken within a time limit (maybe 24/48 hours).
if a person has had covid (within the last 6 months) this would also give a person a covid passport for a period of time (i assume same as the travel 6 months from the date of a positive test).
whatever happens at the end of September we will have details when released in due course.