I was contacted recently by Barclaycard to tell me that I had PBI (payment break insurance) on a credit card, not under their name but underwritten by them, that I'd had around 2005. The premiums were classed as a purchase & interest charged so I'll get that back as well.
It spurred me on to check all my cards so I just phoned each of them up & they started a complaint process over the phone.
I'll have the results by the 28th May.