CPP claim: Martin's template letter

Sprimbly

I have read all that MSE says on the CPP saga. I believe that I fall into the category where the template letter to bank would be the way to go. Took out a CPP policy for card protection, in April 2003 and cancelled it over the phone just in time to stop the direct debit in 2012. I have a list of all the escalating renewal payments I made in between. I recall that I was seduced into this cover by leaflet enclosed to me by the bank which supplied the new credit card which I was taking out at that time. I still use that same credit card supplier. However, the direct debit renewal payments were paid via my current account with a different bank. To which bank should I send my version of the template letter? My instinct is to address it to the credit card supplying bank, with copy to my innocent current account bank. Any comments?