I did most of my training and hours building abroad (mainly USA but some in Europe). I got a job flying a jet before I had even had my CPL issued!
CVs are checked for: fATPL, current IR, current medical, total hours. They don't care where you did it all, but what is relevant to flying airliners.
I think if you have 1st time exam/ flt test passes mention it.
If you have airline type experience mention it. That is, flying into big airports (ideal experience in USA), high altitudes, night, cross country and instrument flying, that sort of thing. I think it shows that you can cope with new things.
You could put on your CV something like
TT 500 hours including xx cross country, xx night, xx instrument
Flown in South America, North America, Europe
Experience of major airports, high altitude airports, etc.
I think it would draw someones attention. After all, most of the flying that UK airline pilots do is outside of the UK and usually at least half the landings are going to be at foreign airports.