Yeah outside of Beckham and Owen, you have to go back to the days of Paul Gascoigne and Chris Waddle as far as world class English players plying their trade overseas.
And before them there were the likes of Trevor Francis and Gary Lineker. Keegan was an absolute beast in Germany but we're going back to the 70s now!
Ironically, an actual Welshman who did play overseas was John Charles. One of the best players of all-time and was voted Juventus' greatest ever import - not bad when that list also includes Platini and Zidane.
British players generally don't play overseas in their prime. They're an especially odd bunch who don't put themselves out there when it comes to adapting to other cultures.