The proper shut-down procedure is to press and hold the STOP button until the word SAVING appears on the display. Then release the button. When the word SAVING disappears and the clock comes back, then it is in Standby and it's safe to turn off power.
I see that the Standby command is shown on the Brennan website page for the Menu list. And I see it on my B2's top level menu. So I guess you could do it that way too.