I never got to see Dark Shadows when it originally aired as my job was 9 to 5, Mon-Fri. When I joined Netflix, I found the complete series available on DVD, from the beginning (before Barnabas appears), through to the end of the series. I finished watching it earlier this year, and at some point, plan on putting it back in my Netflix Queue to watch all over again.
I just looked at Netflix for the movie “House of Dark Shadows” and they only had the TV series. Then I looked on Amazon and they have not come out with the movie on DVD yet.