Kurt,
Thankyou so much. I use a WINDOWS PC. I found that what you suggested worked if (a) I clicked on the first file, (b) held the Ctrl key down, (c) clicked on the second file, then the third file etc (d) then used the Delete key and they all went. I found I had to click on each file in turn, rather than dragging the mouse down to select numerous files as one usually does. But it was still vastly quicker than deleting them separately one at a time. So, many thanks again,
Phil