TinyMce in Sections limited

Hi

I was wondering if this is the norm with Gutenberg installed, but I'm editing a pre-Gutenberg page that uses sections and I'm seeing a limited TinyMce bar instead of the usual (old style) WordPress bar for the text editor (not sure if I'm calling the 'bar' the right thing).

I only have the choice of bold, italicise, underline, quotation, strikeout, align left, centre and right, link, remove link and full screen. So, none of the other choices like choosing headings etc as seen in the screen capture for Sections Overview in the Documentation.

Cheers
-Tina