I think I had Sentinel years ago (circa 1993!) from Barclaycard but haven't had the card for years. Don't think I had it in 2005, when the scheme dates back to. I honestly have no recollection about having card protection from 2005 onwards; I therefore don't know how to fill in the form. Gah!!!!
I got this too and just copied the wording from template 2 on the MoneySavingExpert advice page as it sounded more plausible than template 1 . Since it was money I didn't expect to get back, I just sent it off thinking that will be a bonus if I get anything.