I had been using a free Mac Mail client called Nylas N1 to access the Mens Shed email accounts without getting in the way of my own e-mail accounts in Mail. But now the buggers want money (or the will, after the year's free trial of Nylas Pro is up).
So I went searching for another free basic email client & have settled on Canary beta. Looks good, is simple & uncomplicated, exactly what I need.