rogerw said:
Is there anyway of blocking email from a certain individual or organisation?
In Mail, go to Preferences > Rules and add a rule which says 'If From' contains 'person I really hate' perform the following actions 'Delete mail'.
(It might be best to move it to a folder you create for the purpose rather than delete it, at first anyway, just to check you've got the syntax right and its doing what you intend - voice of bitter experience speaking, having just nearly lost all my inbox..........)