Comment 11 for bug 1633180

Jarno : There is another person working on a selective kernel purging script. See:
http://askubuntu.com/questions/892076/how-to-selectively-purge-old-kernels-all-at-once
And also some exchanges in the general chat room.

I would still be interested to try/test your script, but I do have a workaround that works good enough for my purposes.