On Thu, Jun 30, 2016 at 11:16 PM, Tim ignored_mailbox@yahoo.com.au wrote:
But I seem to recall the conversation pointing the finger at gmail not properly understanding mailing lists
Google and Yahoo is a well-known issue. There is some anti-spam method (which I can't remember the name of now) that Yahoo's servers claim that they do, but then they don't do it right, which is why Google often rejects e-mail from Yahoo servers as spam. At least, this is the argument from the Google side.
In the end though, all spam filters are imperfect, so it's never going to be possible to completely avoid the need to look in your spam folder for false positives.
--Greg