I have a second address with a charity I do work for. All incoming mail is routed to my regular address but I need to be able to send using my second address. I have set up a second account but it results in confusion with incoming mail: mail sometimes appears twice in my inbox, often there is an authentication etc. error. I would like to disable receiving mail on the second account but can't for the life of me see any way of doing it. Help needed, please.