Potential santander PPI claim

Hi,

I have always not really paid any attention to stuff in the press about PPI as I felt sure I didn't have any. However I read the advice on MSE and decided to enquire about it and to do it myself rather than through a claims company.

So I found out I had 2 lots of ppi with Santander (I enquired with them about 3 store cards I had in my early twenties).

The next step is to raise a complaint but I have two options - a standard complaint or Plevin and now I'm not sure what to do. As I said I felt sure I didn't have any ppi as I always avoid insurances etc being added onto things. Any advice/insight, especially into the differences in the claims (amounts/chances of success etc) would be appreciated.

Thanks

Tanya