sorry for the multi-post. I post to forums like i leave voicemail messages...
Not sure if this is to do with my site config, but there is an extra piece of junk info (some floating point number) before the quoted user id.
I just had to change the LogFormat config value to:
LogFormat= "%host %other %other %time1 %methodurl %code %bytesd %refererquot %uaquot %other %lognamequot %extra1
