Short answer - I wouldn't worry about it.
Long answer: The BSS forum does not and never has had an SSL installed.
Google only recently (January - Chrome 56 - see
https://security.googleblog.com/2016/09 ... e-web.html) started flagging sites as "not secure" if the page includes a password form or a request for payment details.
Since there have never been any payment details (credit card numbers / addresses etc.) requested by the BSS forum, there has never been any need to install an SSL. This only leaves the password field - you should, of course, follow the best practice security advice and use a different password for each website you use.
Previously adding an SSL would have added to the forum running costs. There are now free SSLs available (from
https://letsencrypt.org/) which I've installed elsewhere, but their use would be complicated by the fact that the BSS forum uses Cloudflare for additional security measures (to dramatically reduce spam signups, and help against other attacks e.g. cross site scripting etc.) and Cloudflare is generally not compatible with SSLs not supplied by them (and they are particularly expensive for these).
So, it's a trade-off between the benefits off going through Cloudflare, or installing an SSL. And given the nature of the site (no payments details etc.) Cloudflare is the better of the two (IMHO).