NS&I Premium Bonds abroad

There are more than 300,000 unclaimed Premium Bonds held by customers either overseas or location unknown. Holding Premiuim Bonds as an expat isn't straightforward and savers still need a UK bank account and could have to pay tax on their winnings depending on which country they live in. 

Any financial advisers/planners have any advice for savers moving abroad with Premium Bonds - should they cash in and invest elsewhere? Or is the chance of a jackpot worth the extra admin? 

For a piece in The Times this weekend. Thank you!