Hi Mike
Thanks for emailing me at my work address - sorry you can't load your images up, Your images are all, as you thought, S. trifoliolatum. However, I see that having said I personally don't know S. colensoi - it transpires I collected it from the Waimarino Plain in 2005. Its a much bigger plant than S. trifoliolatum, quite glabrous and with deeply toothed leaves.
Cheerio
Peter J. de Lange