Hi neilwilson3412,

thank you very much for your kind words.

I wasn't sure from attached photo, if front surface of mixer is flat or curved, but it seems from another photo https://www.sinkwarehouse.com.au/products/fiona-basin-mixer-black/, that surface is flat, therefore i decided to use that procedure, only as an exercise, but it exists more than one solution of course.

I like the Ed's attempt.
Ciao
Mik