I do tend to use tomato puree when I do them with wraps etc. Did try passata once with a square wrap, and that was messy to say the least. On a thick base, though, I find passata works well.
I'm going to vary it a bit though, and have decided to use a bit of reggae reggae sauce as the sauce base instead...inspired a little by the reggae reggae pizza they used to do in Dominos.