The process is similar for themes - select Appearance -> Themes from the left hand menu to see your themes. When you hover over a theme you will see a link to see Theme Details. Click on this, and then you will see a further link to enable auto-updates.
So go now, and select auto-updates for your plugins and themes, and make your WordPress site more secure.
If you need any assistance with your WordPress site, or if you'd like to try out WordPress for a new site, please do contact our friendly helpdesk by emailing [email protected] or calling 01381600580.