I think I have just figured out what caused the problem for me after about 6 months of pain!
Just now I started doing some clearing up of all the error messages and warnings I was getting in the Output Log and once that was all pretty much cleared up the Print (to screen) messages all started to appear again!
I’m wondering if there’s some kind of limit I was hitting where all my errors and warnings were blocking up the Print printing? That might be something for other people to check too if other things don’t work.