I just used a small carpet knife and some tweezers. Use the knife to get between the flap and the socket’s frame, then the flap should come out with a little pressure applied against the socket’s frame. Getting the flap into the Vero 4k’s socket is the tricky part. You have to put one of the two hinge pins in place, keep the flap from falling into the socket and at the same time push the second hinge pin into its place. It’s kind of self-explanatory as soon as you have the whole thing in front of you…
The important thing is that the small metal thing inside the socket has to be pressed below the bottom part of the flap at the end - this is pushing the flap back into place as soon as a plug is removed. For me, this part has become a bit clunky after the whole operation. So, the flap sometimes doesn’t move back into the closed position properly (a few pushes with the finger tip solve that). But it’s ok as a plug stays in again and it’s better than no flap - or waiting for a return to Sam and a replacement.
But maybe you’d prefer to consult with @sam_nazarko first to talk about a replacement. I guess, both is good. Sam is aware of the issue and should be able to help, I guess.