Widgets not appearing in sidebar on Default Page Template

I want to create a static page with a right sidebar that contains widgets. The Default template contains a space for a right sidebar – the text is shortened to leave a gap on the right, but it doesn’t appear as if there is a sidebar div on the page.

There are no page options other than the Templates Default, Front Page and Full Width.

The right sidebar works fine on the Blog page.

Do I need to buy the Pro theme to be able to use the sidebar area on pages other than the Blog page? Or build my own page template?

I have updated the free Sydney and am using the latest version of the theme.