Actually the problem is now solved.
The problem occurred when I looked up train times and the boxes were hidden, and as I had a similar experience a few months ago, which was not then associated with train timetables, I thought it was back. It was only when I chanced my arm with different resolutions and font sizes I decided to email Network Rail.
The result was that they were aware of the issue and were addressing it!
Makes yer fink doan it!