Pihutze, what a discussion and they are all there - the rule-rules-all, the cowboys, the few common-sensers and even some pilots ;-). Folks, I read all the discussion and summarize for me: it all depends.
One question to the UK flyers. Do you have published VFR traffic patterns and what is their legal status? I remember the very annoying discussion in Germany, you know that country with the hard-headed citizens, on traffic patterns and in the end the lawyers had to clear that traffic patterns are just guidelines, nothing else (there even is a published expert opinion, can't find it now).
I would treat a "log final" call at an uncontrolled airfield the same as "ILS established" on a controlled airport, where this is just an information and if time permits the controller will clear to land you well before the established machine is in final. Once the "long final" guy enters final, it has to fiddle emself into the traffic at the pattern, that easy?