I now have six PIC16F18446 chips programmed as dual digit seven segment display controllers.
Beautifully simple approach. There are 7 output pins driving the anodes of the LED's in parallel and the common cathode of each digit returns via a resistor to a dedicated output pin for each digit. 9 output pins in total.
8 input pins provide the pair of nybbles needed for the pair of digits.
Each digit is turned on 50% of the time and with the microcontroller running with it's internal clock set to 1MHz the digit refresh rate is flicker free at 150Hz.
I now have to wait for the PCB's to arive in a few days before I can have any more fun.