Neil,
You do present an interesting metacognitive challenge; your Fire Safety and the Fire Safety Plan course sounds like the one-time, self-paced, content-based course. This sounds similar to an online course I had to take from one of the provincial ministries on client information privacy policy. It took about three hours to complete the online "read and answer" course, after which I received a certificate that I needed to give to my employer. There was no contact with anyone during or after the course. Also similar was the Canadian Language Benchmark Boot Camp Certificate I needed to give for credit in my Teaching English as a Second Language certificate courses. You work through the course material at your own pace; after reading each section, you write the test until you get the required percentage to pass; then, you can move on to the next section. At the end, you get a certificate. At no time, do you need or have access to another person. There is an email address to contact someone should you have any problems.
In your course, do you have a group of people taking this self-paced course at the same time? If yes, then your suggestion of having a group discussion forum where they could reflect and discuss what they already know based on their work experience and why they are taking the course before they start the course would help bring your individual workers together into a learning cohort. After starting the course, as you suggest, you could have an open discussion forum during the course that would allow for on-going course-content discussion among the participants further developing the learning cohort. When they have finished the course, you could have a "Looking back - Looking forward" discussion forum where participants could discuss how they plan to apply what they learned in the course to their work-place.
I look forward to learning from the feedback and comments you receive from the other participants as your situation certainly introduces an interesting metacognitive challenge.
Out of confusion comes clarity.
Leonne