"Westerner" doesn't work, does it? I come from 'western' Europe and I live in 'western' Europe, albeit in a different country.
I like 'European' but that doesn't work either in the context of someone living in a different European country from the one they were born in.
I quite like the term 'Brit', as in British, but unfortunately, even though I'm proud of my heritage, it has mainly negative connotations for many these days:
"There go the drunken Brits."
"Those Brits always come over here and start trouble."
And so on and so forth...
I don't like 'expat' - where do I come from if I'm an 'expat'? What does it say about me that's not the same as 'foreigner'? It also has, as Mr Fook observes, old-fashioned connotations of the days of Empire (the British Empire), and old colonialists sitting in their clubs with a gin and tonic (usually on the veranda), and lording it over the 'natives'. No thank you (but I wouldn't mind the G&T if you're offering, although a Vodka & Tonic would be better).
No, 'expat' is definitely a word that's gone past its use by date.
You can call me British, if you wish. I don't mind that so much. However, as mentioned above, please don't shorten it.
However, why label me by my nation of birth or my geo-political location on the face of the planet Earth.
Much better that you call me by my name. And they call me Mr
Tibbs... er, sorry... Mr Syzygy