Thanks so much!
Finally had the chance to run this, using the Border Forests from the book as a two-session adventure. Had a great time, combat felt slow at first but once the players got the 'rhythm' of the combat and knew their options after a couple of fights it worked really well. Character creation was great too, the options and descriptors all felt flavourful and distinct, and the starter adventure was a good way to introduce everything - although the boss did get wiped out much faster than I expected thanks to three back-to-back critical hits from the players! The only real problem that came up was that Heinous Magic seems to have less powerful options than the other magics, especially at higher levels.
Overall, a great game which I'll probably run again!