We'll get that in the next update!
5.1 releasing today/tomorrow 
WIth regards to adding a feature image to a blog post, I followed your instructions above, but I then get two copies of the featured image on the main blog page. So that doesn't work!!! Should I duplicate the image file, give a different name and store it in a different location? Would that resolve the issue?
The front page is showing all the content of the blog post. The way around this is to position the ##more## where you want the content to truncate on the front page. So put this before the image and it won't appear
https://help.pulsecms.com/article/15-blog
Yes, I did mean blog title rather than blog header. My mistake. It's the one Pulse users add in the Meta Section. I want that to appear both on my blog page and at the top of the individual blog post. Is this achievable?
Absolutely - can you see from the image above? Mine "blog title" is there.
e.g.
Before click through:
After click through:
This is done by default. Are you using Blocs for this site or Pulse on its own?