Thanks paul.
There are many ways to skin a cat.
But for each 7 seg display you need a driver.
Then why not use the 74HC595 and also get the shift register.
If you use BCD to 7 segment drivers you are limiting yourself to
0 to F.
With your method we have full use of the 7-seg display.
It seems obvious to me!
As soon as I get my sensors of the protoboard I will be trying
out your idea.