Just what is happening with the English-language DVD release?!

I have the first volume of "Saber Rider" in English on DVD, released by Anchor Bay; I ordered my copy from AmazonUK. But it's been months now, and, as far as I can tell, no more volumes have so far been released or are even slated to be released. What's going on with the English-language version on DVD? Does anyone know?