how do i turn off the auto on clock of a cannon gas cooker?

On my Cannon, I press the "Manual" button.

http://www.gotogasdocs.co.uk/f/m/Cannon/Cookers/Harmony%20Mk2%20IUM.pdf

Page 7.

Note the clock also needs to be set properly!

You should be able to find a manual for your own cooker easily enough. just do a Google search for "cannon MODEL manual" (replacing "MODEL" with your own info, naturally.

Surprised you didn't do this anyway.

acp
July 2017