Fantastic!
I've been waiting for this to work as it's been pretty hit-and-miss for me in adding fonts and I've just been too lazy to ask on MR for help, now I don't have to.
Thanks Valoric, I know you've had a lot of praise for Sigil (I know as I've heap a little bit of that myself), but I can't thank you enough for it. As having an application that takes out all the work that would otherwise take quite some time to learn as a novice ebook maker means that I can make books that look good and still take my time to learn how this all works. I don't have to wait until I've gathered enough knowledge to hand-code them, I can just plough straight in.
Thanks again!