Thanks for the info Leroy11! It just seemed weird the partnership was one way - but definately agree on the IST - JFK deal.

As a result of Delta not taking my TL tickets for miles I ended up sending in a Qualiflyer group application form along with my boarding cards to the US service center. Question is: will they give me credit for that flight? I did see some "no past credit" statements on this list so have an uneasy feeling!