Bit provocative there methinks.
'Brits who choose to live abroad are called "ex pats"' . by whom? Brits who haven't emigrated?
'But foreigners who choose to live in the UK are "immigrants "'. By whom?
I have never had to call myself anything. Can't imagine introducing myself as, Hi, I'm an expat, or Hi I'm an immigrant
In the Canaries, Brits and Northen European visitors and residents are called Guidi's and in Andalucia, Guiri's. It is a term referring to fair skinned people who put handkerchiefs on their heads as protection from the sun, don't bother to use sun cream and wear socks with sandals. Possibly racist, but usually just a piss take.