Murray,
I use Maxim myself. It is a very good capture program but, in my opinion, adequate but not great for processing. The alignment algorithms only appear to deal with translation, rotation and linear scaling. There is a plugin that might do what you want:
http://winfij.homeip.net/maximdl/undistort.html
RegiStar is pretty clunky to use but is
very good at image registration which is just about all it does.
PixInsight can be challenging to learn and doesn't suit everybody but it is a very powerful image processing package.
There may be other options so perhaps others will chime in...
Cheers,
Rick.