Another one that slipped past me..
Did you take out a joint loan with a partner - then later you divorced? Was there PPI on that loan and did your partner claim and get all of the money back.. with you being non the wiser?
http://www.thisismoney.co.uk/money/saving/article-3871798/Thousands-divorced-women-deprived-PPI-payouts-NatWest-Royal-Bank-Scotland-receive-compensation.html
Other banks apparently complied with rules and shared the pay-out between separated partners.