I have solved this problem with the help of suggestions from Rick Macdougall, Matthew Newton, and Bob Menchal. Thanks chaps!
suggestions were using spamassassin -D to debug, corrupt Rule in .cf file, and corrupt bayes database. It turned out to be a problem with one of the rules in one of the many .cf files I have "acquired" over the last year or so (thanks Matt!). Because the pressure was on, and after having tried to identify which file it was unsuccessfully, I just trashed (backed up) the lot and started again. This is because I do not know how to get the debugging to tell me which file is being sourced during the 3 minute delay it causes. If anyone can help me with this, I can perhaps come back with more detail. A couple of interesting points with version 3.0.4 1) It is obviously sensitive to some RE's that 2.x wasn't 2) It seems to be working better straight out of the box, with minimal learning. Thanks john
