Hi MEB,
It appears I have two Application folders, one outside my Home folder and one inside the Home folder.
I moved both Affinity Designer and Photo into the Application folder in my Home folder and they seem to be working OK at moment.
That's why changing the permissions didn't work it only affected the Applications folder in the Home folder!
I my not very technically minded not sure why I should have two Application folders? and why everything else works from there but not Designer and Photo?
It may be clear to you, many thanks for sticking with this. I will see how to goes.