It seems to be a Halifax thing.
I am not a UK resident for tax purposes and have told Halifax this. They now keep asking for a reference number that the Isle of Man- where I am resident for tax purposes- does not issue. I've tried explaining this, they don't grasp it. But I have found that putting the number 1 in the form makes it go away. Happy days.
As for tax codes and assessments and what not, here in the Isle of Man everyone has to submit a tax return every year, within 6 months of the tax year end. Employees do pay tax in advance by deduction from their wage, the deduction being set by a tax code. But only when the assessment has been done will your tax liability for the year be finalised, and if you've underpaid you've got 30 days to settle. So be careful what you wish for...
My main bank, First Direct, doesn't annoy me at all. They don't have any multiple choice phone menus, you simply ring them up, someone answers the phone, and you tell them what you want. It really is heaven.