Being somewhat old fashioned, I quickly logged on to the Discourse site and turned on mailing list mode!
Now I’m wondering what the best way might be, either in Discourse preferences, or in my mail client, to reduce the length of the Subject line prefix that Discourse adds to each message. Currently it adds ‘[Request Tracker Community Forum]’ and then possibly an additional category. The result is that I can’t see very much of the original subject in my mail client 
I currently filter RT mail into a separate mail folder using sieve, so I may be able to do something there.
Thanks in advance for any other suggestions.
Duncan