They do not try to put you under pressure. You do that yourself. The years and months question was probably killed off by prune. I was taught it in 87 but as an ice breaker. Gives us time to watch you, gives you something to work out and give the RIGHT answer. Its then downhill all the way. There job is to get information out of you not terrify you, trap or trick you.
In my interview it turned out that the Sqn Ldr had had his bags stolen in Bagdad and the Wg Cdr would not let him forget it. Only 8 years later, studying the target sheets, did I find out where H3 was.
Get a map of the world. Find out where the RAF and the rest of the forces are in the world. The map helps your confidence.
Like where is Basra? Umm Quasr, Kuwait, Seeb, Masirah, Ascension etc.
If you come up with an obscure hobby don't worry, we know how to data mine the facts. Really? How do you further your hobby? Have you any interesting examples? How do you rate your espertise? etc. By the end of that topic they will know just how much you really know about taxidermy or whatever.
Don't panic, Good luck.