"Now tell me how many steps has a Spin Turn got.If you are asked to do a Spin Turn you would start at step four of a Natural and not on step one if you were sitting for an examination."
There is no such figure as a Spin Turn in the ISTD, IDTA or UKA syllabi. The specified figure is the Natural Spin Turn with all six steps. That is the figure which would be expected in the examination and that is why we can quote the rise and fall as 'down on 4, rise at end of 5' and not 'down on 1 rise at end of 2'.
"If you were teaching a class and you after going through it a few times wanted to start with the class with the Spin. What exactly would you call it."
Outside the examination room we are free to use terms to suit the situation and the pupils knowledge and experience. It is quite common to refer to the NST as just a spin turn. Many beginners will recognise (if they have been told any names of figures) a combination of 'whisk, chasse and spin turn' because that is easier than 'whisk, chasse from promenade position and natural spin turn'. If I needed to concentrate on part of the figure, then for beginners I might say "let's look at the spin" or "starting from the spin part". If working on technique with more advanced dancers I may refer to steps 4,5 & 6.
Getting back to your earlier post, I repeat, Alex Moore's "Ballroom Dancing" is NOT the technique book. When he wrote his "Revised Technique" in 1948 he also worked on the ISTD Ballroom Faculty committee which produced their technique book. This book was then used for their exams. Since that was 60 years ago anyone who qualified before that book was used must be at least 76 years of age so I doubt if anyone will worry too much about their qualifications.
You also said in another post which I cannot find at the moment, that the pivot in the (natural) spin turn is always 1/2 turn. Please check again!