One of the issues with ghost themes is that they integrate disqus, google analytics and social media. I have looked at a bunch of various such themes, and switched them off. Instead I have injected code for google analytics and disqus directly into the default caspar theme.
This site is now linked to my main blog, and comments are back on: I've changed my gravatar images, and generally fussed about a bit.
I've done a couple of test comments and if this works, I will switch the wordpress blogs over as well.