Is this just happening to me because of some 'hiccup' in the system or is it the case for everyone that when you look at others feedback, its no longer possible to view the past items they have sold or purchased ?

Of course its not an essential part of ebay trading to be able to do this. In fact, I always felt a little voyeuristic when I did trawl through the past purchases of one of my buyers. But the fact is it used to be possible and now (at least for me) it is not.