I've always been enchanted by British steamed puddings. What comfort food they are! Unfortunately my experience with them is quite limited and they take so long to make that experimentation opportunities are limited.
Lately I've noticed some recipes specify both self-rising flour and a healthy dose of baking powder... in the same recipe. Why do you suppose that is, insurance?
I can imagine the recipe working quite well with either, and I'm a tad skeptical of using both. This skepticism (which is borderline fear) results from eating a Spotted Dick at a Yorkshire pub that tasted like a chemical experiment.