Thanks guys for explaining flapback - I remember it well now. Rotorque's explanation was excellent and agrees exactly with the Robinson R22 instructors manual (exercise 5) by RNK Aviation (http://www.rnk.co.uk/himan/) - an excellent colour manual, well worth the read.
Thanks also to Captain206 for your comments. I'm assuming the forces felt on the cyclic stick in forward flight without trim on are directly due to differential lift from the advancing and retreating blades.
LU - Outside Loop's description was correct after all and although the rotors can be considered as a disk for basic flight theory they still are quite individual beasts and will try to flap according to the forces on them at any given time. The repetitive rotation just happens to average out the motion to appear like a disk.
Lu - Yes, I have your diagram, but having it doesn't explain it all away. Yes, the R22 is set-up differently to a 206 and if Joe Pilot is correct about the blades flapping to position before 90 degrees then it doesn't help me, sorry. The fact that the helicopter goes exactly where I push the cyclic stick without having to allow for this 18 degrees offset just leaves me unconvinced. Also, your quick dismissal of Outside Loop's explanation of flap back and in flow role leaves me even more unconvinced that your opinions are sound, sorry.
I'm still going flying the R22 on saturday!