I did try that last night, to no avail. It wasn't until receiving a helpdesk reply describing what ought to have occurred upon clicking the link that I thought to use a different browser. Firefox, normally my trusted favourite, has failed in the task of correctly intrepreting the command within the ashx URL. It was downloading, who knows what, but upon renaming "it" to pdf there was only bemused non-involvement on the part of my pdf reader. Safari, however, responded perfectly. I now have the manual and am about to save the addendum.
Thanks ever so much for your help.