I surmise from the lack of a shooting scripts book for Series 2 that we're not likely to see one from Series 3, but I would be interested to see how the various members of the supporting cast were outlined versus Martha. The fact that I felt we knew more about what made Tish tick might be attributable to the writing versus the acting, but sans scripts it's tough to say. We've all had the opportunity to see the Smith and Jones script courtesy of the BBC, and I do have to say I don't recall there being any more significant character notes for Tish than there were for Martha.