Dave Liney wrote:

If you actually read what I had posted you would have realised that I said
that the car industry does not want the changeover at 12 months or 6 months,
they would rather have a continuous series.

I don't believe you. Surely the motor industry loves the fact that so
many people buy a new car just because the year identifier on the number
plates has changed?

Here in Australia we do have a continuous series and there are no year
identifiers, and the average age of the cars looks lot higher (although
for obvious reasons it's hard to be sure). However, there are still
sales peaks caused by the introduction of new models (and the
discounting to get rid of the old ones) and in June (at the end of the
financial year).