A sad story but I must confess this is not a new situtation. Since OAPs were introduced in 1947-ish it was always clear when leaving the UK the pension will be frozen (although this got changed with the EU and also Swiss residents, and for some unknown reason the Philippines).
BUT:
Us old fogies were ignored as we lose our vote so nobody cared what we thought after 15 years of non-residence, This law has changed - I've got my vote back! Whether I will receive my voting papers and return them in time is wishful thinking at best.