I have made some improvements to the site based on good suggestions from David and Domenico.
There is now an expandable/collapsible banner both on the home page and also on the initial login screen. This contains descriptive information about the purpose of the forum and is a good idea, as previously people would go to the jackrail.space login/sign up page with no information at all about what this is all for. Now some context is given, and may encourage more people to sign up.
I was also requested to open up the site for public access, which I have now done. Please note that naturally anonymous posting is not allowed - one must sign up for that. This of course requires no further explanation.
Please observe that instead of being on a separate website (which, now obsolete, had to be done for technical reasons) the Donate button is now accessible from the banner. Since this site is self hosted by me all the ongoing costs such as virtual machines, domain name fees, email services, and more come out of my pocket, with the generous support of various members from time to time.
I am also delighted to say that the site currently works beautifully on mobile phones - one of the strengths of Discourse software.
Finally, as a result of two recent outages due to software issue, I have spent a considerable amount of time securing the latest updates and ensuring the essential stability of the site.
So far I have not had to send any member a Freddo Frog as a result of my ‘refer a friend’ program. 
We now have 174 users, but having more increases the overall critical mass and usually leads to more and better discussions.
I thank members for their continued interest and support.
As an aside, users may be interested to know about the technical platform. I run a Linux server at DigitalOcean hosted in New York, using Ubuntu linux. Discourse is self hosted, and we are at version 2.9. I use Amazon Simple Email Services (SES) for email delivery, and this provides the highest level of ‘reputation’ so our mail never gets caught in spam traps. Although the free tier of SES costs nothing, I do get invoices for about $0.02 cents every month based on outbound volume! Ubuntu and Discourse are open source, and I am very committed to the open source movement.