SD
Thanks for your interest and responses. I went to your link and it is full of people saying that they have exactly the same problem with IE11 but with no solution(s) offered apart from binning IE11 and going back to IE10 or earlier. Incidentally I couldn't follow your link via IE11 and had to use Chrome instead. The trouble is, this particular problem aside, I prefer IE to Firefox/Chrome.
It would appear therefore that the only solution is to go back to IE10.
Thanks again.