Thank you BasilDV   Adding the Telstra settings as the secondary outgoing server didn't work. Neither did replacing TPG with Telstra as the main outgoing server.   However, while checking the original iPhone TPG outgoing server settings I notiiced the optional username and password fields were in fact blank. Adding this information into the fields appeard to solve the problem and today I have been able to send emails from my I phone when away from home wifi.   Thank you for your help        ... View more