dommie frame number

My recently acquired 57 Dommie has the frame number M14 706** Looking at different sources some show that 57 frames started at No. 71360 and some from N.O.C. records
at 70095 so what is the story of the different information and is my frame number correct ?

The letter M signifies that the factory regarded it as a 1957 model.
End of story.

The difference(s) in year records is that the factory started building the next years models in Sept the previous year. ?
So if you record the production number in Sept, and on 1st Jan, they show different start numbers.
Except that in some years, batches of numbers were reserved for some models, and the numbers jump about all over the place
- the next number in a sequence could be built weeks or months later, it wasn't a neat or tidy sequence at all.

The NOC records came from the actual factory ledgers, so they should in theory know what they are talking about.