Appreciate the info WH. I already have 1-3 DVD. Something strange about the link for the single DVD. Picture is of wrong series and the description talks about season 4 in the future. I could not find that a season 4 DVD was ever made as a single.
I was able to find season 4 on DVD (it didn’t have captions so I had to make do with earphones/lip-reading); it may have been thru Amazon... I will check.