PIXMA TS8160 won't print black and white

Hi there,

I'm printing using a TS8160 on Mac OS X 10.15.1

I'm trying to print in "black and white" mode by selecting the black and white button in the print dialog box, but the printer continues to print in colour.

This is happening across multiple applications - emails, PDFs, Word etc.

Does anyone know if there is a setting somewhere that I need to fix?

Best wishes,

Andrew