Thank you Mark!
Sorry for asking, but how do i do the same in Chrome please?
In Chrome when I try with the written link you kindly provided these thinks happen.
1. After saving the tiddly a clickable link with the letters INS (in blue and with a line under them) appear
2. Hovering the mouse over the letters INS brings up the link in the bottom left of the Chrome window in the downloads area
3. Left clicking on the INS link does nothing.
4. Right clicking on the INS link and selecting open link in a new tab, opens a blank link
5. Right clicking on the INS link and selecting 'Copy Link Address' and then copying that link into a new tab correctly opens the pdf file in the new link chrome window.
So in conclusion I still cant simply click on a pdf link in tiddly and view the pdf.
Hmmm any solutions please?