It is called discrimination no matter which way you look at it. A long time friend of mine retired a few years ago. He still banks in the UK but because he is living in the Philippines he gets no increase.
The UK is very critical of discrimination but only when it applies to others not themselves. In my opinion he should get the increases as he banks in the UK irrespective if there is an agreement between the relevant countries.
The UK government is good at speaking but total liars when it comes to doing the right thing, unless you are an illegal immigrant of course.