Pretty much all my postings for my last 12 years in (-> 2000). As so often, unfortunately, it's not what you know....
Unfortunately, it's one of those RHIP things. Once I was a SNCO and knew a few people, including some in our posting Branch at MoD, I could apply direct pressure and bribery.
Not much consolation if you're not a SNCO, I know, but it will come. Depending what trade/Corps you are, there's a lot you can do to influence your postings simply be course selection.