can't or won't use their judgment along the lines of: 'British officer (complete with letter from the Queen proving this), British family, serving on Sovereign British Territory, employed by HMG, paid in Sterling, paying UK taxes, ergo they are resident British'. But no. You have to prove all of this, from a position of being regarded as Alien and thus hostile.
And I wouldn't leave the private sector out of the debate either - no amount of cajoling would convince 'the world's local bank' that I was, for tax purposes, a UK resident, not even the trappings of the FCO would sway them, I physically had to be back in the UK to find closure on a financial matter!?*. Grrrrrrrr!