@ Mr Tenno
Just for info, the whole "series" thing is a bit of a mine field, hence some of the responce, much of the "internet oracle" stuff is through US eyes and as such is often full of holes as many of our colonial friends still believe that the S30 was hand made for them by Mr K.
Alans your best man for this but my limited understanding is that we tend to look at at it as we do today with facelift type mentality with absolute cutoff dates but in reality the lines were a little more blurred....