What is the point of them?
I had to download one as I was going to the NEC yesterday and it said either proof of vaccination via an NHS covid pass or a negative lateral flow test. I downloaded my covid pass with its QR code which I presumed they would scan and whittled as to whether it would work and would I need ID? I was in a queue of about 5 people. There were two people checking chatting away. I stood there and he handed me a green wrist band, as I took it he said, covid pass, I flashed my phone and off I went. That could have been screen shot from anyones phone. I then put my green wrist band in my pocket and expected to be asked for it at the door, but no. What a pointless exercise.
Either do it or dont, but stop pretending.
I would add it was pretty much empty, as I said there were only five of us split between two queues, if they cant do it properly there, then there really is no hope it will ever be done properly