WD3T - Unable to view a public folder from my iphone / ipad

Problem solved.

I created another folder, cut & pasted some films across and found  that they were now visible on the other devices. When I selected them all and moved them across, they disappeared again. 

So I moved them across in bunches, while checking the mobile device, until I found the ‘bad egg’. 

Hey presto, the files are all visible again.