My experience might not be relatable but from what I gather a successful MSc environmental science application with no bachelor degree.
-What did you do in preparation? asked for a face-to-face meeting to discuss suitability which lead to the opportunity to submit a personal essay. The essay is where it's at I think. I made sure my application contrasted with the personalities of the people I know who were unsuccessful with an application. For example: A friend with a BA in psychology applied for the masters a few years later and was unsuccessful, their defining trait is they invest a lot of time promoting themselves as superhuman. Assuming they'd focused on themselves I described myself in a two statements along the lines of "lonely, obsessive and having spent the last decade chasing everything and nothing through the internet" and "remember too much to be good with people but on the plus side, I remember too much". For the most part the essay focused on how my ideas relate to the course and perhaps arrogantly, how the industry and I desperately need each other.
-Who and number of people that interviewed you? One interviewer and the essay was reviewed by the course head and department head.
-What kind of question did they ask? (about you or portfolio). The interview largely focused around what drives the arrogance that sends an uneducated person to the interview in the first place. See previous comment on the essay. My 2 cents, obviously you want to show a general level of skill however, have one or two special moves up your sleeve; (not a great example) if your chosen course needs expect multiplication as non-negligible entry requirement, make a point of bringing up that all composite numbers are the product of a set of primes and can't be formed by any other set of primes. Show that the some of the stuff the course would introduce is already a matter of interest to you.
-Will they ask your views on current events? Pass, there's a section on ethics the course but as described in "preparation" I covered my thoughts on discounting the general consensus when assessing matters of ethics.
-Any surprising questions? Surprising answer perhaps. Answering honestly "hubris" to "why do you think you are capable?" probably helped in gaining the essay opportunity.
-Duration of the interview? NA, see previous comments on essay.
-What kind of questions did you ask at the end? My 2 cents although NA, Have a related, out your way interesting, contemporary idea at hand and ask for their thoughts, hopefully open dialogue.
-How did you feel at the end of the interview? Ill, rewrote the essay two - three time a day for eleven days.
-Did you get an offer? Yes
Again, this might not be relatable but for what it's worth, I have survived life in spite of myself because I deal with information like a model deals with drink offers in a bar and I hope has translated into something useful.
On an end note: I don't want to give the impression that entry to the course is or was a walk in the park. I have lived built environment research in continuum for years, when I'm trying to sleep I count gas-fired boilers jumping into a skip...