bundle update.bundle exec jekyll build.github-pages or jekyll gem version: jekyll 3.3.1Read time to be displayed for each blog post
https://github.com/ashleyconnor/blog
ashleyconnor.co.uk
Below you can see the fa-clock but no time.

You're missing one small config line. Add words_per_minute: 200 to your _config.yml and it should work.
I'll try that tonight. The docs make it sound like there's a default of 200 already and I only need to add the config entry to override that value.
Reading Time
Enable estimated reading time snippets with read_time: true in YAML Front Matter. 200 has been set as the default words per minute value — which can be changed by adjusting words_per_minutes: in _config.yml.
I guess the keyword here is _adjusting_ - which would imply it was set. My bad.
Going to make a fix to _includes/read-time.html that properly sets words_per_minute if it's omitted from the config file.
The new theme gem way of installing doesn't include it. So the fix for now is adding to your config. That and you'll probably want to add locale: en as well since I noticed that missing.