Collision Cloth not Falling

I have been following the CGBoost tutorial here and am up to video 5:

the collision section starts about here 9:58
It worked the first time, but ever since for several tries, the cloth has not fallen. It just remains a plane suspended over the object it is supposed to fall on.

Then I went to this tutorial by Blender Know How.

Following this I was able to make a cloth fall and drape.
But when I went back to CGBoost video and used those settings, the cloth/plane still would not fall.

The file has been through a crash of my system and reinstallation of both Linux Mint and Blender 2.8, but except for this everything else in the file works.

Any assistance would be appreciated in getting through this stage.