So, here is where we are in Buxton World:
King of Trees is now on iBooks as well as Kindle and Nook.
The Nostalgia Gambit is still not on iBooks! I don't know why, since KoT made it onto that platform in days, but TNG is still not there after two months.
The Sixth Discipline had a fantastic month! Thanks to the Bookbub promotion, it has already topped 15,000 (free) copies in May, and that's on Kindle alone. It's also now free in the UK and Canadian Kindle stores. The sequel No Safe Haven is selling well in consequence.
Lastly, my science fiction romance (working title is now Saronna's Gift) is back from being critiqued by my writers group, and is now undergoing some revisions. I'm still aiming for a late summer release.