Thanks for those replies'
I have the JAR and FAA definitions of V1 but I find them inconclusive. Different operators appear to use varying criteria. For example, some colleagues flying the A320 say that at V1, they can make a decision to STOP OR GO. Where as some Boeing and BAe 146 drivers will tell you that at V1, you go flying, end of story! In other words, V1 is the DECISION TO GO speed.
I am aware of the buffers built into V1 determinaton (recognition and reaction time, average pilot ability etc), however I still find myself short on a good series of diagrams and explanations to use for new sprogs.
Anyway, thanks for the input to date.