After much research and frustration I discover that if I delete all cookies the home page appears correctly.
I then process a manual order, end it and wish to return to the Home page to find that the error occurs again, that is, a logo and a horizintal bar but no content.
Delete cookies, all OK again.
What is causing this behaviour?
My customers are experiencing this as well and I am losing business.
Other than abandoning Prestashop, what can I do to resolve this issue?