It will never happen Britain is more than bust and monies for folks living abroad and forgotten will be nobodies priority. But campaign away if it makes you happy. Indeed, highlighting it will only spark off some eagle-eyed bean counter to work out how to link up bank accounts, home office passport entry/exit to UK and DWP computers to determine residence and then stop any fraudulent claims and even backdate them if thought necessary. You can see some Sir Humphrey shilling 100s of mullions savings to the minister and getting a gong for it.
https://www.thenational.scot/news/23903863.dwp-plan-monitor-benefit-claimants-bank-accounts/