UTFT_Demo_480x320 unable to change font size or type

I'm running the demo s/w on the 480 x 320 screen and it works OK.
I am using a genuine UNO - no clones here.

Fairly new to programming, but I don't understand how to change the font.
Whatever I change it to using

extern uint8_t BigFont[];

for example.

It still only does the small font!

Any ideas

Very few 480x320 screens will run on a Uno with genuine UTFT library.

Please post a link to the actual screen that you have bought. e..g.. Ebay sale.

David.