"you cannot rotate the rear wheels to give better access?"
The problem is Richard it's not possible to get the connector end of the grease gun into the u/j. I've even tried grinding the connector (which is on a flexible pipe) but it still won't get in there. In desperation I've ordered one of these:
http://www.ebay.co.uk/itm/281470781572?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
off Ebay. It looks a bit slimmer so I'll report back when I get it if it works.