The suggestion on yahoo was that an archive of electronic copies would be available to all and recent issues would only be available to members on a password protected area of the AUK website. The option to opt out of the paper magazine would no doubt come with that.
Seems like a sensible way forward to me. I'd probably take advantage of the archive (particularly if it is set up such that you can search for keywords and events, albeit possibly a big undertaking for a volunteer organisation).