Your Bath Spa mail account now has an undo send feature, actually it just gives you up to 30 seconds after you click send to change your mind. It's the same prompt you get when you delete or move email - a small yellow window with an 'undo' option.
Go to the little cog icon in the upper righthand corner and select “Settings.” About a third of the way down the page you’ll see the “Undo Send” section. You can choose 5, 10, 20 and 30 second delay.
Scroll to the bottom of the page and 'save' your settings.