Android 7.0 How do I change the Font size for text messages

[Android Central Question]

I found a site that advised to go to the settings via the cog on the drop down menu - Accessibility - Display Size -

However, I only have two options, 'Small' and 'Default', with no option for 'Large' Font.

Does anyone know how to get larger than 'Default' font ?
Or is there a message app with it's own option for Large Font, or any 'Add on' app that would allow me to increase Text message size Please ?