As requested, below is what I did to get it working, quite straight forwards really (and pretty obvious!):-
1) After following all the instructions on setting up the email, I was having no joy, searching this (excellent) forum for an answer but getting nowhere
2) Quite by chance, I stumbled into the Edit Email set-up (Admin Panel - Emails - Select email address)
3) Pretty obvious from this screen that I had not set up a fair chunk of the email settings. Entered the relevant user logon data for the mailbox we use, mail (POP3) account info and SMTP settings
As soon as I completed point 3, email started to work just perfectly and I have not had an issue since :)