After trying various approaches, I have now installed and tested an option for members only to get an email when a new blog post goes live, with the option of limiting this to certain categories (eg Member Only) if you prefer.
The process does require members to access their WordPress personal account dashboard, which is not normally visible. Instructions are supplied in the NotHarry profile page (which is not the same as the WordPress user profile to which you will be redirected) and that becomes available on the Member Login tab AFTER you have logged in.
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