Just make sure you don't retire to the ex-colonies such as Aus, NZ, SA or Canada. Your pension is frozen the day you start it when living in countries such as those. EU, US, parts of Asia are fine.
They can spend >GB1B on GCHQ spying efforts but not GB400m per year to index veterans pensions in those countries.
From what I have seen of NI, make very sure to check their facts, they can and do make a mess of things at times! (I am involved with Canadian Alliance of British Pensioners who are one group fighting this discriminatory action)