Silver Streak is a plicata x (broken colour x plicata). The pollen parent of Ibiza is a (plicata x complicated parentage nearly all plicatas) x sibling.
I think you are right Tom. My seedling looks more like a blend. There are probably enough plicatas in its ancestry to create one if I crossed it with another plicata.
Leslie. I would like to create a better version of it. I need to search for something nice with good form to cross it with.