Solved! Go to Solution.
First you need to be in basic mail mode, to do that click on settings (cog wheel in top right corner) and then select more settings. At the bottom of the left hand pane select switch to basic mail. Once in basic mail, select settings and click Go in the top right of the window. At the bottom of the resulting page you will see the forwarding options.
Thank you. Why BT could not have put that on their information page I do not know. Your instructions are perfect.