Many thanks for your reply, Taffycat. I did as you suggested but found that the box was already unticked, so had to think again. I did, however, eventually discover an answer and wonder if others have had this experience also.
The paperclips were showing in the preview section on my email page but not at the top of the individual messages when opened. Apparently I have now to double-click the paperclip in the preview, which then opens the message in a separate window. I then have to double-click the attachment box at the head of the message and.....behold....., the attachment fills the screen! It seems very longwinded and I assume that the many updates which, daily, emanate from Microsoft are responsible. I still can't help wondering whether this is just me or whether other people's emails are behaving the same way; it only started at the end of last week.