Artie's suggested
Rule works a treat and I will now change the action to delete. Now all I have to do is to have my mobile do the same thing...
As long as the account is IMAP ou don't have to change anything on your mobil device. Your non-mobil device will move the offending messages to the trash — assuming it is on and running and Mail is running in either background or foreground.
That's true as long as both devices are signed into the same iCloud account and Mail is set to sync on both.
This may seem contrary to generic IMAP, but I have my iPhone set so it does not sync one of my mail accounts with the same account on my iMac. If I delete an e-mail on the iPhone, it remains on my iMac. Reversing the settings on each device would do the vice versa deletion.
